diff --git a/tivars/types/complex.py b/tivars/types/complex.py
index ff6f9f5..037e215 100644
--- a/tivars/types/complex.py
+++ b/tivars/types/complex.py
@@ -133,10 +133,10 @@ def __complex__(self):
     def __format__(self, format_spec: str) -> str:
         def make_imag(entry: 'RealEntry') -> str:
             match entry.type_id:
-                case 0x18 | 0x21:
+                case TIRealFraction.type_id | TIRealPiFraction.type_id:
                     return format(entry, format_spec).replace("/", "i/")
 
-                case 0x1C:
+                case TIRealRadical.type_id:
                     return f"{entry:{format_spec}} * i"
 
                 case _:
@@ -247,8 +247,8 @@ def imag_type(self) -> type['RealEntry']:
     def clear(self):
         super().clear()
 
-        self.real_subtype_id = 0x0C
-        self.imag_subtype_id = self._type_id if self._type_id is not None else 0x0C
+        self.real_subtype_id = TIComplex.type_id
+        self.imag_subtype_id = self._type_id if self._type_id is not None else TIComplex.type_id
 
     def components(self) -> (RealEntry, RealEntry):
         """
@@ -258,13 +258,11 @@ def components(self) -> (RealEntry, RealEntry):
         return self.real, self.imag
 
     def get_min_os(self, data: bytes = None) -> OsVersion:
-        data = data or self.data
-
-        match max(data[0], data[9]):
-            case 0x0C:
+        match self.get_version(data):
+            case 0x00:
                 return TI_83.OS()
 
-            case 0x1B:
+            case 0x0B:
                 return TI_84P.OS("2.55")
 
             case _:
@@ -274,10 +272,10 @@ def get_version(self, data: bytes = None) -> int:
         data = data or self.data
 
         match max(data[0], data[9]):
-            case 0x0C:
+            case TIComplex.type_id:
                 return 0x00
 
-            case 0x1B:
+            case TIComplexFraction.type_id:
                 return 0x0B
 
             case _:
@@ -326,7 +324,8 @@ def load_string(self, string: str):
             self.real = self.real_type(parts[0])
 
         except (TypeError, ValueError):
-            for type_id in [0x00, 0x18, 0x1C, 0x20, 0x21]:
+            for type_id in [TIReal.type_id, TIRealFraction.type_id, TIRealRadical.type_id,
+                            TIRealPi.type_id, TIRealPiFraction.type_id]:
                 if type_id == self.real_subtype_id:
                     continue
 
diff --git a/tivars/types/group.py b/tivars/types/group.py
index 467873c..e5e777d 100644
--- a/tivars/types/group.py
+++ b/tivars/types/group.py
@@ -10,7 +10,10 @@
 from tivars.data import *
 from tivars.models import *
 from tivars.var import TIEntry, SizedEntry
+from .appvar import *
 from .gdb import TIGraphedEquation
+from .list import *
+from .tokenized import *
 
 
 class TIGroup(SizedEntry, register=True):
@@ -75,10 +78,10 @@ def group(entries: Sequence[TIEntry], *, name: str = "GROUP") -> 'TIGroup':
                 vat[0] |= entry.raw.flags
 
             match entry.type_id:
-                case 0x05 | 0x06 | 0x15 | 0x17:
+                case TIProgram.type_id | TIProtectedProgram.type_id | TIAppVar.type_id | TIGroup.type_id:
                     vat += bytearray([len(name), *name])
 
-                case 0x01 | 0x0D:
+                case TIRealList.type_id | TIComplexList.type_id:
                     vat += bytearray([len(name) + 1, *name, 0])
 
                 case _:
@@ -113,7 +116,7 @@ def ungroup(self, data: bytes = None) -> list[TIEntry]:
             _, version = data.read(2)
 
             match type_id := type_byte[0] & 63:
-                case 0x05 | 0x06 | 0x15 | 0x17:
+                case TIProgram.type_id | TIProtectedProgram.type_id | TIAppVar.type_id | TIGroup.type_id:
                     *_, page, length = data.read(4)
 
                     if length > 8:
@@ -122,7 +125,7 @@ def ungroup(self, data: bytes = None) -> list[TIEntry]:
 
                     name = data.read(length)
 
-                case 0x01 | 0x0D:
+                case TIRealList.type_id | TIComplexList.type_id:
                     *_, page, length = data.read(4)
 
                     if length > 7:
diff --git a/tivars/types/tokenized.py b/tivars/types/tokenized.py
index 34cbcc5..517633d 100644
--- a/tivars/types/tokenized.py
+++ b/tivars/types/tokenized.py
@@ -303,7 +303,7 @@ def protect(self):
         Cast this program to a protected program
         """
 
-        self.type_id = 0x06
+        self.type_id = TIProtectedProgram.type_id
         self.coerce()
 
     def unprotect(self):
@@ -311,7 +311,7 @@ def unprotect(self):
         Cast this program to an unprotected program
         """
 
-        self.type_id = 0x05
+        self.type_id = TIProgram.type_id
         self.coerce()
 
     @Loader[bytes, bytearray, BytesIO]
@@ -359,13 +359,13 @@ def coerce(self):
         doors &= b"\xEF\x68" in self.data and self.data.index(b"\xEF\x68") > 0
 
         match self.type_id, any(token in self.data for token in self.asm_tokens) | doors:
-            case 0x05, False:
+            case TIProgram.type_id, False:
                 self.__class__ = TIProgram
-            case 0x05, True:
+            case TIProgram.type_id, True:
                 self.__class__ = TIAsmProgram
-            case 0x06, False:
+            case TIProtectedProgram.type_id, False:
                 self.__class__ = TIProtectedProgram
-            case 0x06, True:
+            case TIProtectedProgram.type_id, True:
                 self.__class__ = TIProtectedAsmProgram