diff --git a/devito/ir/equations/algorithms.py b/devito/ir/equations/algorithms.py
index 175311d22e..8913f81dde 100644
--- a/devito/ir/equations/algorithms.py
+++ b/devito/ir/equations/algorithms.py
@@ -8,7 +8,7 @@
                           ConditionalDimension)
 from devito.types.array import Array
 from devito.types.basic import AbstractFunction
-from devito.types.dimension import MultiSubDimension, SubDimensionThickness
+from devito.types.dimension import MultiSubDimension, Thickness
 from devito.data.allocators import DataReference
 from devito.logger import warning
 
@@ -213,7 +213,7 @@ def _(expr, mapper, rebuilt, sregistry):
     _concretize_subdims(expr.implicit_dims, mapper, rebuilt, sregistry)
 
 
-@_concretize_subdims.register(SubDimensionThickness)
+@_concretize_subdims.register(Thickness)
 def _(tkn, mapper, rebuilt, sregistry):
     if tkn in mapper:
         # Already have a substitution for this thickness
diff --git a/devito/operator/operator.py b/devito/operator/operator.py
index 0a7e0dc7da..9bfdcdc255 100644
--- a/devito/operator/operator.py
+++ b/devito/operator/operator.py
@@ -31,7 +31,7 @@
                           split, timed_pass, timed_region, contains_val)
 from devito.types import (Buffer, Grid, Evaluable, host_layer, device_layer,
                           disk_layer)
-from devito.types.dimension import SubDimensionThickness
+from devito.types.dimension import Thickness
 
 
 __all__ = ['Operator']
@@ -642,9 +642,9 @@ def _prepare_arguments(self, autotune=None, **kwargs):
         for d in reversed(toposort):
             args.update(d._arg_values(self._dspace[d], grid, **kwargs))
 
-        # Process SubDimensionThicknesses
+        # Process Thicknesses
         for p in self.parameters:
-            if isinstance(p, SubDimensionThickness):
+            if isinstance(p, Thickness):
                 args.update(p._arg_values(grid=grid, **kwargs))
 
         # Process Objects
diff --git a/devito/types/dimension.py b/devito/types/dimension.py
index d3e531594a..6f7ae89c67 100644
--- a/devito/types/dimension.py
+++ b/devito/types/dimension.py
@@ -22,7 +22,7 @@
            'VirtualDimension', 'Spacing', 'dimensions']
 
 
-Thickness = namedtuple('Thickness', 'left right')
+SubDimensionThickness = namedtuple('SubDimensionThickness', 'left right')
 
 
 class Dimension(ArgProvider):
@@ -535,16 +535,12 @@ def _arg_check(self, *args, **kwargs):
 # The Dimensions below are exposed in the user API. They can only be created by
 # the user
 
-class SubDimensionThickness(DataSymbol):
+class Thickness(DataSymbol):
     """A DataSymbol to represent a thickness of a SubDimension"""
 
     __rkwargs__ = DataSymbol.__rkwargs__ + ('root', 'side', 'local', 'value')
 
-    def __new__(cls, *args, **kwargs):
-        root = kwargs.pop('root')
-        side = kwargs.pop('side')
-        local = kwargs.pop('local')
-
+    def __new__(cls, *args, root=None, side=None, local=False, **kwargs):
         newobj = super().__new__(cls, *args, **kwargs)
         newobj._root = root
         newobj._side = side
@@ -633,7 +629,7 @@ def __init_finalize__(self, name, parent, thickness, **kwargs):
         super().__init_finalize__(name, parent)
         thickness = thickness or (None, None)
         if any(isinstance(tkn, self._thickness_type) for tkn in thickness):
-            self._thickness = Thickness(*thickness)
+            self._thickness = SubDimensionThickness(*thickness)
         else:
             self._thickness = self._symbolic_thickness(thickness=thickness)
 
@@ -648,7 +644,7 @@ def _symbolic_thickness(self, **kwargs):
         kwargs = {'dtype': np.int32, 'is_const': True, 'nonnegative': True}
 
         names = ["%s_%stkn" % (self.parent.name, s) for s in ('l', 'r')]
-        return Thickness(*[Symbol(name=n, **kwargs) for n in names])
+        return SubDimensionThickness(*[Symbol(name=n, **kwargs) for n in names])
 
     @cached_property
     def symbolic_min(self):
@@ -735,7 +731,7 @@ class SubDimension(AbstractSubDimension):
 
     __rargs__ = AbstractSubDimension.__rargs__ + ('local',)
 
-    _thickness_type = SubDimensionThickness
+    _thickness_type = Thickness
 
     def __init_finalize__(self, name, parent, thickness, local,
                           **kwargs):
@@ -756,12 +752,13 @@ def middle(cls, name, parent, thickness_left, thickness_right, local=False):
 
     @memoized_meth
     def _symbolic_thickness(self, thickness=None):
-        kwargs = {'dtype': np.int64, 'is_const': True, 'nonnegative': True,
+        kwargs = {'dtype': np.int32, 'is_const': True, 'nonnegative': True,
                   'root': self.root, 'local': self.local}
 
         names = ["%s_%stkn" % (self.parent.name, s) for s in ('l', 'r')]
-        return Thickness(*[SubDimensionThickness(name=n, side=s, value=t, **kwargs)
-                           for n, s, t in zip(names, (LEFT, RIGHT), thickness)])
+        return SubDimensionThickness(*[Thickness(name=n, side=s, value=t, **kwargs)
+                                       for n, s, t
+                                       in zip(names, (LEFT, RIGHT), thickness)])
 
     @cached_property
     def _interval(self):