Built by the Ordnance Department and conformed to the 15 ton weight limit. It was based on the British Medium Mark II.
In 1931 the hull 37 mm gun was removed, and a .30 cal MG was added for anti-aircraft fire.
Originally had a 47 mm gun in the turret and a 37 mm gun in the hull. The 37 mm gun could fire a 1.91 lb shell at a muzzle velocity of 2,550'/sec.