The SKS Intrafuse Compliance System offers everything you need to transform your original SKS into a modern weapon system. Each kit includes the SKS Intrafuse Stock, TAPCO 20rd Magazine, Gas Piston, Operating Rod, and 25-port Muzzle Brake. Modeled after the Yugo grenade launcher, the muzzle brake is designed to mount to barrels with a 14x1 RH thread pitch. Per U.S. Sec 922R, our components will count as 8 compliance parts with the muzzle brake adding an additional part for weapons with threaded barrels. All products are manufactured in the USA by TAPCO Inc.