Based on the needs of the British Purchasing Commission the Ram tanks that were being produced were altered to take a 25 pdr. Was very similar to the US M7 Priests.
Early vehicles had welded superstructure. Later models had cast nose, towing hook for ammo trailer, auxiliary generator, and mounts for antiaircraft machine guns.
There was a hatch on the left side for loading ammunition. The fighting compartment could be covered with a canvas. The gun was installed in a special cradle.
The driver was placed on right and gun was offset to the left.