diff --git a/src/dodal/devices/zebra/zebra.py b/src/dodal/devices/zebra/zebra.py
index 6a0e6cc2155..79a6f21deca 100644
--- a/src/dodal/devices/zebra/zebra.py
+++ b/src/dodal/devices/zebra/zebra.py
@@ -7,11 +7,15 @@
 from bluesky.protocols import Movable
 from ophyd_async.core import (
     AsyncStatus,
+    DeviceMock,
     DeviceVector,
     SignalRW,
     StandardReadable,
     StrictEnum,
+    callback_on_mock_put,
+    default_mock_class,
     observe_value,
+    set_mock_value,
 )
 from ophyd_async.epics.core import epics_signal_r, epics_signal_rw
 
@@ -88,6 +92,17 @@ class SoftInState(StrictEnum):
     NO = "No"
 
 
+class InstantArmMock(DeviceMock["ArmingDevice"]):
+    async def connect(self, device: ArmingDevice) -> None:
+        callback_on_mock_put(
+            device.arm_set, lambda *_, **__: set_mock_value(device.armed, 1)
+        )
+        callback_on_mock_put(
+            device.disarm_set, lambda *_, **__: set_mock_value(device.armed, 0)
+        )
+
+
+@default_mock_class(InstantArmMock)
 class ArmingDevice(StandardReadable, Movable[ArmDemand]):
     """A useful device that can abstract some of the logic of arming.
     Allows a user to just call arm.set(ArmDemand.ARM)"""