The PP-90 is a compact Russian submachine gun designed for close-quarters combat and covert operations. When folded, it resembles a metal briefcase or large radio, making it highly concealable. The weapon uses a blowback action and fires 9x18mm Makarov rounds from a 30-round magazine. To deploy, the user unfolds the front grip, stock, and trigger mechanism. While its unusual design offers a stealth advantage, it is known for poor ergonomics, uncomfortable handling, and limited accuracy beyond short range. Production was small, and it saw limited use primarily with special forces and police units in the 1990s.