M4anti-tank mineThe M4 is a high-explosive metal-cased anti-tank blast mine; it is similar to the M1 and M1A1 but incorporates auxiliary fuze wells in the base. The mine is initiated by pressure, but is resistant to blast because of the "spider" pressure plate. Pressure on the spider is transferred to the head of the fuze, where it breaks an internal shear pin and depresses an internal collar to release a striker retaining ball. This releases the spring-loaded striker onto the detonator to initiate the booster and main charge. Since these mines are likely to be old and contain cocked strikers, they should not be disarmed. Anti-lift devices may be present in the auxiliary fuze wells. Easily detectable.Diameter: 203mm Height: 102mm Weight: 4.8kg Explosive: 1.8kg Range: 400m Explosive/filler type: TNTUSA