X23 Non-Nuclear Electromagnetic Pulse Cannon
From Halopedia, the Halo wiki
The X23 NNEMP Cannon takes up much of the Gremlin's dorsal surface and is much bulkier than the far smaller and more portable W/AV G/GNR.
The X23 NNEMP Cannon is a weapon in service with the UNSC Marine Corps. Gremlin support vehicles are equipped with one of these turrets for anti-armor combat.[1] Its special EMP ability is entirely ineffective against infantry.
