The MKII A3, a high-explosive-fragmentation, anti-personnel, defensive, time-delay fused, hand grenade.

The MKII A3 hand grenade is painted olive drab, with a yellow band around the top of the fuse well. Its slang name is Pineapple because of its pineapple shape and external deep serrations. These serrations delineate the fragmentation of the body when the hand grenade explodes. It was the standard-issue hand grenade used during World War II and also saw limited service in later conflicts.

The MKII A3 was gradually phased out of service as a newer series of hand grenade was introduced. Due to the tremendous quantity manufactured during World War II the MKII A3 was still in limited issue with the Allied forces throughout the 1950s and 1960s.

Allied naval operations were one of the last users of the MKII A3 when it was finally withdrawn from military service and replaced with the more favorable baseball grenade. It was not until later that the MKII A3 would make a return thanks to the Deimos Arms Manufacturer improving on the design and making the MKII A4 used today.