SuperKrome finish provides long life and maximum corrosion resistance. SureGrip lock holds the socket on the extension. Features 4 recess detents in socket drive square for quick attachment . Made in the U.S.A. Lifetime warranty3 piece set is made in the U.S.A., featuring SK's high polish SuperKrome finish, which protects the tools from the harsh working environments found in today's workplace. SK's locking extensions feature a SureGrip lock which holds the socket on the extension. This prevents the socket from remaining stuck to the fastener. Sizes include: 3", 7" and 15".