diff --git a/src/gt4py/_core/definitions.py b/src/gt4py/_core/definitions.py
index 21d157f022..e949627f59 100644
--- a/src/gt4py/_core/definitions.py
+++ b/src/gt4py/_core/definitions.py
@@ -378,6 +378,7 @@ class DeviceType(enum.IntEnum):
     https://github.com/dmlc/dlpack/blob/main/include/dlpack/dlpack.h
     """
 
+    INVALID_DEVICE = -1
     CPU = 1
     CUDA = 2
     # CPU_PINNED = 3    # noqa: ERA001
@@ -388,11 +389,18 @@ class DeviceType(enum.IntEnum):
     ROCM = 10
     # CUDA_MANAGED = 13 # noqa: ERA001
     # ONE_API = 14      # noqa: ERA001
+    GPU = (  # TODO whatever makes sense
+        CUDA
+        if cp is not None
+        and not (cp.cuda.runtime.is_hip if hasattr(cp.cuda.runtime, "is_hip") else False)
+        else ROCM
+    )
 
 
 CPUDeviceTyping: TypeAlias = Literal[DeviceType.CPU]
 CUDADeviceTyping: TypeAlias = Literal[DeviceType.CUDA]
 ROCMDeviceTyping: TypeAlias = Literal[DeviceType.ROCM]
+GPUDeviceTyping: TypeAlias = Literal[DeviceType.GPU]
 
 
 DeviceTypeT = TypeVar(
@@ -403,9 +411,7 @@ class DeviceType(enum.IntEnum):
 )
 
 
-CUPY_DEVICE_TYPE = (
-    None if not cp else (DeviceType.ROCM if cp.cuda.runtime.is_hip else DeviceType.CUDA)
-)
+CUPY_DEVICE_TYPE = DeviceType.GPU
 
 
 @dataclasses.dataclass(frozen=True)
diff --git a/src/gt4py/next/allocators.py b/src/gt4py/next/allocators.py
index 097b57371b..bb133e33df 100644
--- a/src/gt4py/next/allocators.py
+++ b/src/gt4py/next/allocators.py
@@ -89,7 +89,7 @@ def is_field_allocation_tool(obj: Any) -> TypeGuard[FieldBufferAllocationUtil]:
 
 def is_field_allocation_tool_for(
     obj: Any, device: core_defs.DeviceTypeT
-) -> TypeGuard[FieldBufferAllocationUtil]:
+) -> TypeGuard[FieldBufferAllocationUtil[core_defs.DeviceTypeT]]:
     return is_field_allocator_for(obj, device) or is_field_allocator_factory_for(obj, device)