diff --git a/src/dodal/devices/zebra/zebra.py b/src/dodal/devices/zebra/zebra.py
index 4000235172f..66718e8fe23 100644
--- a/src/dodal/devices/zebra/zebra.py
+++ b/src/dodal/devices/zebra/zebra.py
@@ -171,10 +171,10 @@ def __init__(self, prefix: str, name: str = "") -> None:
         self.pulse_1 = PulseOutput(prefix + "PULSE1")
         self.pulse_2 = PulseOutput(prefix + "PULSE2")
 
-        self.out_ttl_pvs: DeviceVector[SignalRW] = DeviceVector(
+        self.out_ttl_pvs: DeviceVector[SignalRW[float]] = DeviceVector(
             {i: epics_signal_rw(float, prefix + f"OUT{i}_TTL") for i in range(1, 5)}
         )
-        self.out_lvds_pvs: DeviceVector[SignalRW] = DeviceVector(
+        self.out_lvds_pvs: DeviceVector[SignalRW[float]] = DeviceVector(
             {i: epics_signal_rw(float, prefix + f"OUT{i}_LVDS") for i in range(1, 4)}
         )
         super().__init__(name)