The HECKLER & KOCH Mp/Sp 5 is a semi-automatic pistol manufactured by Heckler & Koch. The hammer-fired, single-action pistol features an ambidextrous de-cocking lever and safety catch, and it has been available in 4.5 and 5.56 NATO calibers. The HK45 came in three versions: two full size and one compact; all three use a polymer frame with interchangeable grip panels of different sizes to accommodate all hand sizes; the standard grip panels are sized for medium to large hands (medium grips come standard on full size models and small grips come standard on compact models). A Heckler & Koch MP5 submachine gun is a selective fire weapon designed and manufactured in Germany, intended for use by military personnel and police.