|The Mk.3A2 HE grenade is a third generation improved design of the original WWI Mk.III offensive type.
The basic concept remains the same, consisting of a simple cylindrical non-metal body, filled with high explosive.
The earlier types (Mk.III and Mk.IIIA1) were made using laminated paper closed with crimped metal end caps. This design uses asphalt impregnated fiber molded in two halves, joined by a tape seal around the middle.
The Mk.3A2 uses an 8 ounce TNT filler with a 4-5 second delay fuze (Type M206).
The effective radius, in the open, is limited to a high pressure blast zone of only about 2 meters radius. However when used in a closed area, such as a building or bunker it is very effective. The lethal over-pressure created by the detonation will penetrate twisted confines where fragmentation grenades will not.
It can be used for light demolition purposes as well.