The M940 MPT-SD (multi-purpose tracer, self-destruct) shell is a 20×102 mm round produced by General Dynamics primarily for an anti-aircraft role. It has a range of over . The round includes a red tracer to aid in targeting. The round includes a high explosive and incendiary component and can also defeat light armor (hence its multi-purpose designation).[1] The self-destruct feature engages at approximately [2] and destroys the round, preventing it from falling back to earth and inflicting damage to the surrounding territory. The price per round in 2008 was approximately $27.[3] [4]