The P90 is a compact personal defense weapon, also known as a PDW, that was designed to replace 9x19mm Parabellum firearms. Compact yet powerful, the P90 has been effective for vehicle crews, support personnel, special forces, and counter-terrorist groups. While development started in 1986, production began later in 1990 which is where the “90” in the name comes from and when the ammunition was redesigned and shortened.