diff --git a/pyop2/codegen/builder.py b/pyop2/codegen/builder.py
index 6f3460c29..5931e20ad 100644
--- a/pyop2/codegen/builder.py
+++ b/pyop2/codegen/builder.py
@@ -15,7 +15,7 @@
                                           PreUnpackInst, Product, RuntimeIndex,
                                           Sum, Symbol, UnpackInst, Variable,
                                           When, Zero)
-from pyop2.datatypes import IntType, PetscMatType
+from pyop2.datatypes import IntType, mat_dtype
 from pyop2.op2 import (ALL, INC, MAX, MIN, ON_BOTTOM, ON_INTERIOR_FACETS,
                        ON_TOP, READ, RW, WRITE)
 from pyop2.utils import cached_property
@@ -871,7 +871,7 @@ def add_argument(self, arg):
             pack = MixedDatPack(packs, access, dtype,
                                 interior_horizontal=interior_horizontal)
         elif isinstance(arg, MatKernelArg):
-            argument = Argument((), PetscMatType(), pfx="mat")
+            argument = Argument((), mat_dtype, pfx="mat")
             maps = tuple(self._add_map(m, arg.unroll)
                          for m in arg.maps)
             pack = arg.pack(argument, access, maps,
@@ -881,7 +881,7 @@ def add_argument(self, arg):
         elif isinstance(arg, MixedMatKernelArg):
             packs = []
             for a in arg:
-                argument = Argument((), PetscMatType(), pfx="mat")
+                argument = Argument((), mat_dtype, pfx="mat")
                 maps = tuple(self._add_map(m, a.unroll)
                              for m in a.maps)
 
diff --git a/pyop2/datatypes.py b/pyop2/datatypes.py
index ab4e25087..ae0c4a922 100644
--- a/pyop2/datatypes.py
+++ b/pyop2/datatypes.py
@@ -71,34 +71,11 @@ def dtype_limits(dtype):
     return info.min, info.max
 
 
-class PetscObjectType(lp.types.OpaqueType):
-    def __init__(self, name="PetscObject"):
+class OpaqueType(lp.types.OpaqueType):
+    def __init__(self, name):
         super().__init__(name=name)
 
     def __repr__(self):
-        return type(self).__name__
+        return self.name
 
-
-class PetscISType(PetscObjectType):
-    def __init__(self):
-        super().__init__(name="IS")
-
-
-class PetscVecType(PetscObjectType):
-    def __init__(self):
-        super().__init__(name="Vec")
-
-
-class PetscMatType(PetscObjectType):
-    def __init__(self):
-        super().__init__(name="Mat")
-
-
-class PetscPCType(PetscObjectType):
-    def __init__(self):
-        super().__init__(name="PC")
-
-
-class PetscKSPType(PetscObjectType):
-    def __init__(self):
-        super().__init__(name="KSP")
+mat_dtype = OpaqueType("Mat")
diff --git a/pyop2/op2.py b/pyop2/op2.py
index 5031c6fa3..cd60360f0 100644
--- a/pyop2/op2.py
+++ b/pyop2/op2.py
@@ -36,7 +36,7 @@
 import atexit
 
 from pyop2.configuration import configuration
-from pyop2.datatypes import PetscISType, PetscVecType, PetscMatType, PetscPCType, PetscKSPType  # noqa: F401
+from pyop2.datatypes import mat_dtype  # noqa: F401
 from pyop2.logger import debug, info, warning, error, critical, set_log_level
 from pyop2.mpi import MPI, COMM_WORLD, collective
 
diff --git a/test/unit/test_direct_loop.py b/test/unit/test_direct_loop.py
index 355510997..ecec731a4 100644
--- a/test/unit/test_direct_loop.py
+++ b/test/unit/test_direct_loop.py
@@ -270,7 +270,7 @@ def test_passthrough_mat(self):
         petsc_mat.setValues([0, 2, 4], [0, 2, 4], np.zeros((3, 3), dtype=PETSc.ScalarType))
         petsc_mat.assemble()
 
-        arg = op2.PassthroughArg(op2.PetscMatType(), petsc_mat.handle)
+        arg = op2.PassthroughArg(op2.mat_dtype, petsc_mat.handle)
         op2.par_loop(kernel, iterset, arg)
         petsc_mat.assemble()