diff --git a/lib2/h3-strings.adb b/lib2/h3-strings.adb
index 48538a8..44a431d 100644
--- a/lib2/h3-strings.adb
+++ b/lib2/h3-strings.adb
@@ -1,19 +1,19 @@
 with Ada.Unchecked_Deallocation;
 
 package body H3.Strings is
-	BUFFER_ALIGN: constant := 16;
+	BUFFER_ALIGN: constant := 128; -- TODO: change it to a reasonably large value.
 
 	type Shift_Direction is (SHIFT_LEFT, SHIFT_RIGHT);
 
-	function To_Character_Array (Str: in Elastic_String) return Character_Array is
+	function To_Item_Array (Str: in Elastic_String) return Item_Array is
 	begin
 		return Str.Buffer.Slot(Str.Buffer.Slot'First .. Str.Buffer.Last);
-	end To_Character_Array;
+	end To_Item_Array;
 
 	-- return the buffer capacity excluding the terminator
 	function Get_Capacity (Str: in Elastic_String) return System_Size is
 	begin
-		return Str.Buffer.Slot'Length - 1;
+		return Str.Buffer.Slot'Length - Terminator_Length;
 	end Get_Capacity;
 
 	-- private. return the buffer capacity including the terminator
@@ -38,16 +38,16 @@ package body H3.Strings is
 		return Str.Buffer.Last;
 	end Get_Last_Index;
 
-	function Get_Item (Str: in Elastic_String; Pos: in System_Index) return Character_Type is
+	function Get_Item (Str: in Elastic_String; Pos: in System_Index) return Item_Type is
 	begin
 		return Str.Buffer.Slot(Pos);
 	end Get_Item;
 
 	-- unsafe as it exposes the internal buffer which can go away.
 	-- assume the system address is equal to the thin pointer in size.
-	function Get_Slot_Pointer (Str: in Elastic_String) return Thin_Character_Array_Pointer is
+	function Get_Slot_Pointer (Str: in Elastic_String) return Thin_Item_Array_Pointer is
 		A: System.Address := Str.Buffer.Slot(Str.Buffer.Slot'First)'Address;
-		P: Thin_Character_Array_Pointer;
+		P: Thin_Item_Array_Pointer;
 		for P'Address use A'Address;
 		pragma Import (Ada, P);
 	begin
@@ -165,7 +165,7 @@ package body H3.Strings is
 	<<COPY_OVER>>
 		if Shift_Pos <= 0 then
 			-- no shift is required. copy the entire string including th
-			Str.Buffer.Slot(First .. Last + 1) := Tmp.Buffer.Slot(First .. Last + 1);
+			Str.Buffer.Slot(First .. Last + Terminator_Length) := Tmp.Buffer.Slot(First .. Last + Terminator_Length);
 			Str.Buffer.Last := Last;
 			return;
 		end if;
@@ -178,12 +178,12 @@ package body H3.Strings is
 				Mid: System_Size := Shift_Pos - Shift_Size;
 			begin
 				Str.Buffer.Slot(First .. Mid) := Tmp.Buffer.Slot(First .. Mid);
-				Str.Buffer.Slot(Mid + 1 .. Last - Shift_Size + 1) := Tmp.Buffer.Slot(Shift_Pos + 1 .. Last + 1);
+				Str.Buffer.Slot(Mid + 1 .. Last - Shift_Size + Terminator_Length) := Tmp.Buffer.Slot(Shift_Pos + 1 .. Last + Terminator_Length);
 				Str.Buffer.Last := Last - Shift_Size;
 			end;
 		else
 			Str.Buffer.Slot(First .. Shift_Pos - 1) := Tmp.Buffer.Slot(First .. Shift_Pos - 1);
-			Str.Buffer.Slot(Shift_Pos + Shift_Size .. Last + Shift_Size + 1) := Tmp.Buffer.Slot(Shift_Pos .. Last + 1);
+			Str.Buffer.Slot(Shift_Pos + Shift_Size .. Last + Shift_Size + Terminator_Length) := Tmp.Buffer.Slot(Shift_Pos .. Last + Terminator_Length);
 			Str.Buffer.Last := Last + Shift_Size;
 		end if;
 	end Prepare_Buffer;
@@ -200,7 +200,12 @@ package body H3.Strings is
 		Str.Buffer := Empty_Buffer'Access;
 	end Purge;
 
-	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Character_Type; Repeat: in System_Size := 1) is
+	function Calc_Inc_Capa (Str: in Elastic_String; Inc: in System_Size) return System_Size is
+	begin
+		return H3.Align(Get_Length(Str) + Inc + Terminator_Length, BUFFER_ALIGN);
+	end Calc_Inc_Capa;
+
+	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Item_Type; Repeat: in System_Size := 1) is
 		Act_Pos: System_Index := Pos;
 		Act_Inc: System_Size := Repeat;
 	begin
@@ -208,43 +213,43 @@ package body H3.Strings is
 			Act_Pos := Str.Buffer.Last + 1;
 		end if;
 
-		Prepare_Buffer (Str, H3.Align(Get_Length(Str) + Act_Inc + 1, BUFFER_ALIGN), Act_Pos, Act_Inc);
+		Prepare_Buffer (Str, Calc_Inc_Capa(Str, Act_Inc), Act_Pos, Act_Inc);
 		Str.Buffer.Slot(Act_Pos .. Act_Pos + Act_Inc - 1) := (others => V);
 	end Insert;
 
-	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Character_Array) is
+	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Item_Array) is
 		Act_Pos: System_Index := Pos;
 	begin
 		if Act_Pos > Str.Buffer.Last then
 			Act_Pos := Str.Buffer.Last + 1;
 		end if;
 
-		Prepare_Buffer (Str, H3.Align(Get_Length(Str) + V'Length + 1, BUFFER_ALIGN), Act_Pos, V'Length);
+		Prepare_Buffer (Str, Calc_Inc_Capa(Str, V'Length), Act_Pos, V'Length);
 		Str.Buffer.Slot(Act_Pos .. Act_Pos + V'Length - 1) := V;
 	end Insert;
 
 -- TODO: operator "&" that returns a new Elastic_String
-	procedure Append (Str: in out Elastic_String; V: in Character_Type; Repeat: in System_Size := 1) is
+	procedure Append (Str: in out Elastic_String; V: in Item_Type; Repeat: in System_Size := 1) is
 	begin
 		Insert (Str, Get_Last_Index(Str) + 1, V, Repeat);
 	end Append;
 
-	procedure Append (Str: in out Elastic_String; V: in Character_Array) is
+	procedure Append (Str: in out Elastic_String; V: in Item_Array) is
 	begin
 		Insert (Str, Get_Last_Index(Str) + 1, V);
 	end Append;
 
-	procedure Prepend (Str: in out Elastic_String; V: in Character_Type; Repeat: in System_Size := 1) is
+	procedure Prepend (Str: in out Elastic_String; V: in Item_Type; Repeat: in System_Size := 1) is
 	begin
 		Insert (Str, Get_First_Index(Str), V, Repeat);
 	end Prepend;
 
-	procedure Prepend (Str: in out Elastic_String; V: in Character_Array) is
+	procedure Prepend (Str: in out Elastic_String; V: in Item_Array) is
 	begin
 		Insert (Str, Get_First_Index(Str), V);
 	end Prepend;
 
-	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Character_Type; Repeat: in System_Size := 1) is
+	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Type; Repeat: in System_Size := 1) is
 		Act_To_Pos, Repl_Len: System_Size;
 	begin
 		if From_Pos <= To_Pos and then From_Pos <= Str.Buffer.Last then
@@ -258,7 +263,7 @@ package body H3.Strings is
 				Prepare_Buffer (Str, Get_Hard_Capacity(Str), Act_To_Pos, Repl_Len - Repeat, SHIFT_LEFT);
 				Act_To_Pos := From_Pos + Repeat - 1;
 			elsif Repeat > Repl_Len then
-				Prepare_Buffer (Str, Get_Hard_Capacity(Str), From_Pos, Repeat - Repl_Len, SHIFT_RIGHT);
+				Prepare_Buffer (Str, Calc_Inc_Capa(Str, Repeat - Repl_Len), From_Pos, Repeat - Repl_Len, SHIFT_RIGHT);
 				Act_To_Pos := From_Pos + Repeat - 1;
 			else
 				Prepare_Buffer (Str);
@@ -267,7 +272,7 @@ package body H3.Strings is
 		end if;
 	end Replace;
 
-	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Character_Array) is
+	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Array) is
 		Act_To_Pos, Repl_Len: System_Size;
 	begin
 		if From_Pos <= To_Pos and then From_Pos <= Str.Buffer.Last then
@@ -281,7 +286,7 @@ package body H3.Strings is
 				Prepare_Buffer (Str, Get_Hard_Capacity(Str), Act_To_Pos, Repl_Len - V'Length, SHIFT_LEFT);
 				Act_To_Pos := From_Pos + V'Length - 1;
 			elsif V'Length > Repl_Len then
-				Prepare_Buffer (Str, Get_Hard_Capacity(Str), From_Pos, V'Length - Repl_Len, SHIFT_RIGHT);
+				Prepare_Buffer (Str, Calc_Inc_Capa(Str, V'Length - Repl_Len), From_Pos, V'Length - Repl_Len, SHIFT_RIGHT);
 				Act_To_Pos := From_Pos + V'Length - 1;
 			else
 				Prepare_Buffer (Str);	
@@ -307,7 +312,7 @@ package body H3.Strings is
 		return Str.Buffer = Str2.Buffer or else Str.Buffer.Slot(Get_First_Index(Str) .. Get_Last_Index(Str)) = Str2.Buffer.Slot(Get_First_Index(Str2) .. Get_Last_Index(Str2));
 	end "=";
 
-	function "=" (Str: in Elastic_String; Str2: in Character_Array) return Standard.Boolean is
+	function "=" (Str: in Elastic_String; Str2: in Item_Array) return Standard.Boolean is
 	begin
 		return Str.Buffer.Slot(Get_First_Index(Str) .. Get_Last_Index(Str)) = Str2;
 	end "=";
@@ -331,4 +336,5 @@ package body H3.Strings is
 	begin
 		Unref_Buffer (Str.Buffer);
 	end Finalize;
+
 end H3.Strings;
diff --git a/lib2/h3-strings.ads b/lib2/h3-strings.ads
index 7fa60db..58e7073 100644
--- a/lib2/h3-strings.ads
+++ b/lib2/h3-strings.ads
@@ -1,19 +1,23 @@
 with Ada.Finalization;
 
 generic
-	--type Character_Type is private;
-	type Character_Type is (<>);
-	Terminator: Character_Type;
+	--type Item_Type is private;
+	type Item_Type is (<>);
+	G_Terminator_Length: System_Zero_Or_One;
+	G_Terminator_Value: Item_Type;
 package H3.Strings is
 
+	Terminator_Length: constant System_Zero_Or_One := G_Terminator_Length;
+	Terminator_Value: constant Item_Type := G_Terminator_Value;
+
 	type Elastic_String is private;
-	type Character_Array is array(System_Index range <>) of Character_Type;
-	--type Character_Array_Pointer is access all Character_Array;
+	type Item_Array is array(System_Index range <>) of Item_Type;
+	--type Item_Array_Pointer is access all Item_Array;
 
-	subtype Thin_Character_Array is Character_Array(System_Index'Range);
-	type Thin_Character_Array_Pointer is access Thin_Character_Array;
+	subtype Thin_Item_Array is Item_Array(System_Index'Range);
+	type Thin_Item_Array_Pointer is access Thin_Item_Array;
 
-	function To_Character_Array (Str: in Elastic_String) return Character_Array;
+	function To_Item_Array (Str: in Elastic_String) return Item_Array;
 
 	function Get_Capacity (Str: in Elastic_String) return System_Size;
 	pragma Inline (Get_Capacity);
@@ -29,47 +33,48 @@ package H3.Strings is
 	function Get_Last_Index (Str: in Elastic_String) return System_Size;
 	pragma Inline (Get_Last_index);
 
-	function Get_Item (Str: in Elastic_String; Pos: in System_Index) return Character_Type;
+	function Get_Item (Str: in Elastic_String; Pos: in System_Index) return Item_Type;
 	pragma Inline (Get_Item);
 
 	-- unsafe
-	function Get_Slot_Pointer (Str: in Elastic_String) return Thin_Character_Array_Pointer;
+	function Get_Slot_Pointer (Str: in Elastic_String) return Thin_Item_Array_Pointer;
 	pragma Inline (Get_Slot_Pointer);
 
 	function Is_Shared(Str: in Elastic_String) return Standard.Boolean;
 	pragma Inline (Is_Shared);
 
-	procedure Purge (Str: in out Elastic_String);
 	procedure Clear (Str: in out Elastic_String);
+	procedure Purge (Str: in out Elastic_String); -- clear and reset the buffer to Empty_Buffer.
 
-	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Character_Type; Repeat: in System_Size := 1);
-	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Character_Array);
+	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Item_Type; Repeat: in System_Size := 1);
+	procedure Insert (Str: in out Elastic_String; Pos: in System_Index; V: in Item_Array);
 
-	procedure Append (Str: in out Elastic_String; V: in Character_Type; Repeat: in System_Size := 1);
-	procedure Append (Str: in out Elastic_String; V: in Character_Array);
+	procedure Append (Str: in out Elastic_String; V: in Item_Type; Repeat: in System_Size := 1);
+	procedure Append (Str: in out Elastic_String; V: in Item_Array);
 
-	procedure Prepend (Str: in out Elastic_String; V: in Character_Type; Repeat: in System_Size := 1);
-	procedure Prepend (Str: in out Elastic_String; V: in Character_Array);
+	procedure Prepend (Str: in out Elastic_String; V: in Item_Type; Repeat: in System_Size := 1);
+	procedure Prepend (Str: in out Elastic_String; V: in Item_Array);
 	
-	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Character_Type; Repeat: in System_Size := 1);
-	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Character_Array);
+	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Type; Repeat: in System_Size := 1);
+	procedure Replace (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Array);
 
 	procedure Delete (Str: in out Elastic_String; From_Pos: in System_Index; To_Pos: in System_Size);
 
 	function "=" (Str: in Elastic_String; Str2: in Elastic_String) return Standard.Boolean;
-	function "=" (Str: in Elastic_String; Str2: in Character_Array) return Standard.Boolean;
+	function "=" (Str: in Elastic_String; Str2: in Item_Array) return Standard.Boolean;
 
 private
 	type Buffer_Record(Capa: System_Size) is limited record
 		Refs: System_Size := 1;
-		Slot: Character_Array(1 .. Capa);
+		Slot: Item_Array(1 .. Capa) := (others => Terminator_Value);
 		Last: System_Size := 0;
 	end record;
 
 	type Buffer_Pointer is access all Buffer_Record;
 
 	--Empty_Buffer: aliased Buffer_Record(1);
-	Empty_Buffer: aliased Buffer_Record := (Capa => 1, Refs => 0, Slot => (1 => Terminator), Last => 0);
+	-- Use 1 slot to hold the terminator value regardless of th terminator length in Empty_Buffer.
+	Empty_Buffer: aliased Buffer_Record := (Capa => 1, Refs => 0, Slot => (1 => Terminator_Value), Last => 0);
 
 	type Elastic_String is new Ada.Finalization.Controlled with record
 		Buffer: Buffer_Pointer := Empty_Buffer'Access;
diff --git a/lib2/h3.ads b/lib2/h3.ads
index 1731721..3b343ec 100644
--- a/lib2/h3.ads
+++ b/lib2/h3.ads
@@ -25,6 +25,8 @@ package H3 is
 	--subtype System_Index is System_Size range 0 .. (System_Size'Last - 1);
 	subtype System_Index is System_Size range (System_Size'First + 1) .. System_Size'Last;
 
+	subtype System_Zero_Or_One is System_Word range 0 .. 1;
+
 	type Storage_Pool_Pointer is access all System.Storage_Pools.Root_Storage_Pool'Class;
 
 	type System_Byte_Array is array(System_Index range<>) of System_Byte;
diff --git a/lib2/hello.adb b/lib2/hello.adb
index 39e2e8f..eb0597b 100644
--- a/lib2/hello.adb
+++ b/lib2/hello.adb
@@ -12,8 +12,10 @@ with Ada.Wide_Text_IO;
 with Ada.Assertions;
 
 use type H3.System_Size;
+
 procedure hello is
-	package S is new H3.Strings(Wide_Character, Wide_Character'Val(0));
+	package S is new H3.Strings(Standard.Wide_Character, 1, Wide_Character'Val(0));
+	package S_I is new H3.Strings(Integer, 1, 16#FF#);
 
 	--type Global_Pool is new System.Storage_Pools.Root_Storage_Pool with null record;
 	P1: aliased System.Pool_Global.Unbounded_No_Reclaim_Pool;
@@ -60,9 +62,11 @@ procedure hello is
 		first := S.Get_First_Index(Str);
 		last := S.Get_Last_Index(Str);
 		Ada.Text_IO.Put (Name & " len:" & len'Img & " capa:" & capa'Img & " first:" & first'img & " last:" & last'img & " => ");
-		Ada.Wide_Text_IO.Put_line (Standard.Wide_String(S.To_Character_Array(Str)));
+		Ada.Wide_Text_IO.Put_line (Standard.Wide_String(S.To_Item_Array(Str)));
 
-		pragma Assert (S.Get_Item(Str, S.Get_Last_Index(Str) + 1) = Wide_Character'Val(0));
+		if S.Terminator_Length > 0 then
+			pragma Assert (S.Get_Item(Str, S.Get_Last_Index(Str) + 1) = S.Terminator_Value);
+		end if;
 	end print_string_info;
 
 begin
@@ -170,7 +174,7 @@ begin
 
 		declare
 			-- unsafe way to access the internal buffer.
-			arr: constant S.Character_Array := S.To_Character_Array(Str);
+			arr: constant S.Item_Array := S.To_Item_Array(Str);
 		begin
 			Ada.Wide_Text_IO.Put ("STR[1] => [");	
 			for i in arr'Range loop
@@ -284,7 +288,6 @@ begin
 		pragma Assert (S.Get_First_Index(Str2) = 1);
 		pragma Assert (S.Get_Last_Index(Str2) = 107);
 		pragma Assert (S."="(Str2, "AACCABQh! Hello, world!  donkey>donkeyXABCDEEXTRA THIS IS FANTASTIC ELASTIC STRING WRITTEN FOR H3 => ABCDEF"));
-		--S.Replace (Str2, 10000, 'Q'); -- constraint error
 
 		S.Prepend (Str2, '>', 3);
 		print_string_info (Str2, "Str2");
@@ -342,15 +345,22 @@ begin
 		pragma Assert (S.Get_Last_Index(Str2) = 85);
 		pragma Assert (S."="(Str2, "Hello, bee!  donkey>donkeyXABCDEEXTRA THIS IS FANTASTIC ELASTIC STRING WRITTEN FOR HH"));
 
+		S.Replace (Str2, 8, 10, "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ"); 
+		print_string_info (Str2, "Str2");
+		pragma Assert (S.Get_Length(Str2) = 160);
+		pragma Assert (S.Get_First_Index(Str2) = 1);
+		pragma Assert (S.Get_Last_Index(Str2) = 160);
+		pragma Assert (S."="(Str2, "Hello, ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ!  donkey>donkeyXABCDEEXTRA THIS IS FANTASTIC ELASTIC STRING WRITTEN FOR HH"));
+
 		declare
-			arr: constant S.Thin_Character_Array_Pointer := S.Get_Slot_Pointer(Str);
-			arr2: constant S.Thin_Character_Array_Pointer := S.Get_Slot_Pointer(Str2);
+			arr: constant S.Thin_Item_Array_Pointer := S.Get_Slot_Pointer(Str);
+			arr2: constant S.Thin_Item_Array_Pointer := S.Get_Slot_Pointer(Str2);
 			use type H3.System_Word;
 		begin
 			print_string_info (Str, "Str");
 			
 			Ada.Wide_Text_IO.Put ("STR(By-Pointer) [");	
-			for i in S.Get_First_Index(Str) .. S.Get_Last_Index(Str) + 1 loop -- this must loop to the terminating null.
+			for i in S.Get_First_Index(Str) .. S.Get_Last_Index(Str) + S.Terminator_Length loop -- this must loop to the terminating null.
 				Ada.Wide_Text_IO.Put (arr.all(i));
 			end loop;
 			Ada.Wide_Text_IO.Put_Line ("]");	
@@ -358,14 +368,14 @@ begin
 			print_string_info (Str2, "Str2");
 		
 			Ada.Wide_Text_IO.Put ("Str2(By-Pointer) [");	 -- this must loop to the terminating null.
-			for i in S.Get_First_Index(Str2) .. S.Get_Last_Index(Str2) + 1 loop
+			for i in S.Get_First_Index(Str2) .. S.Get_Last_Index(Str2) + S.Terminator_Length loop
 				Ada.Wide_Text_IO.Put (arr2.all(i));
 			end loop;
 			Ada.Wide_Text_IO.Put_Line ("]");	
 		end;
 
 		--declare
-		--	arr: constant Standard.Wide_String := S.To_Character_Array(str);
+		--	arr: constant Standard.Wide_String := S.To_Item_Array(str);
 		--begin
 		--	Ada.Wide_Text_IO.Put_Line (arr);	
 		--end;
@@ -403,5 +413,18 @@ begin
 		Ada.Text_IO.Put_Line(Q.Get_Item_Pointer(T2).X'Img);
 	end;
 
+
+	declare
+		t1: S_I.Elastic_String;
+	begin
+		S_I.Append (t1, 20, 5);
+		S_I.Prepend (t1, 30, 2);
+
+		Ada.Text_IO.Put_Line ("-------------------------------");
+		for i in S_I.Get_First_Index(t1) .. S_I.Get_Last_Index(t1) loop
+			Ada.Text_IO.Put  (" " & S_I.Get_Item(t1, i)'Img);
+		end loop;
+		Ada.Text_IO.Put_Line ("");
+	end;
 end;