22 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. Provides long life and maximum corrosion resistance. All sockets feature SK's SureGrip® hex design, which drives the side of the fastener, not the corner, to avoid edge breakage which can occur on rusted or damaged fasteners when a traditional straight cornered hex tool is used. Set includes the SK SuperKrome® Professional Ratchet featuring a completely enclosed ratcheting mechanism which is easy to remove and replace for cleaning or rebuilding. Triple tooth contact provides smooth ratcheting action with little back movement. Professional series ratchets also feature hardened pawl and teeth for durability and long life. Diamond knurled grip provides sure handling, even when oily. Chamfered ends help lead the socket over fastener heads. Set also includes a SuperKrome® spark plug socket, and some SuperKrome® extensions.