The Mk 3 mine or Mine G.S. Mk III was a British anti-tank mine used during World War II. The mine had a cylindrical tin lower body with a steel pressure plate which sits on top of a shear-wire restrained spring-loaded striker. Sufficient pressure on the cover shears the restraining wire, allowing the striker spring to push the striker into a 0.11 grams (1.7 gr) percussion cap. The flash from the percussion cap is transferred to the No.27 detonator which sits in the center of the mine.