Calibers: 5.7x28mm or 9mm. Capacity: 20-round (5.7x28mm) or 15, 18- or 20-round (9mm) magazine. Barrel: 3.5”, 4.5”, 5”. Grips: Textured polymer, modular backstrap. Sights: Fiber-optic front, serrated rear. Finish: Black, gray, FDE, or OD green. Features: Striker fire trigger, accessory rail, mag well. Some models with threaded barrel.