This Vickers, Sons & Maxim 37mm MkIII "Pompom" is on display at the Canadian War Museum in Ottawa. The MkIII pattern is quite scarce, with less than one hundred ever made. It is built around the 37 x 124mm cartridge, firing a 1.25 pound explosive or armor piercing projectile. This one (or one of the same model) was mounted on the CGS Canada, a coastal patrol vessel built by VSM in 1904 for the Canadian Fisheries service. Firing fully automatically at 300 rounds/minute, the "pompom" (so named for the sound of its firing) was capable of tremendous firepower, although few ever saw much use in combat. Only the Boers made much use of them as land artillery, and by WW1 most were relegated to antiaircraft use.