Three men of the Canadian Infantry Brigade preparing to send a hand grenade into a sniper's hideout in the Maltese Mountains, Campochiaro, Italy, 23 October 1943. Photo by Alexander M. Stirton. Department of National Defence / National Archives of Canada, PA-136198.

Developed during World War I, the Mills bomb continued to serve as the standard British grenade during the Second World War. It was made of cast iron deeply serrated to fragment easily. Pulling the grenade's pin released a lever holding the striker, which in turn ignited the fuse. The Mills bomb was initially set with a seven-second delay which was reduced to four seconds after the fall of France in the spring of 1940, when it was found that seven seconds allowed the Germans enough time to pick up the grenade and throw it back. The Mills bomb could be thrown to about 30 yards' range.