12-point socket openings are an exact fit for double hex fasteners. They also offer mulitple positions for engaging square and hex fasteners， which is especially helpful when access is limited. The socket opening's radiused corners prevent round-off by gripping fasteners on their flat sides， and not their corners. Die-stamped markings are permanently impressed into the steel and can't wear off. They're designed with large， clear size numbers that are easy to read even in low light settings. The polished chrome plating protects against corrosion and wipes clean to a mirror finish. The deepest parts of the socket well， where nickel and chrome layers cannot be deposited in sufficient thickness， are protected with an additional thin layer of clear coat， rather than conventionally-used silver paint， to prevent rust. Four detent grooves provide a secure connection with the retaining ball of a drive tool. Radiused corners reinforce the drive end by eliminating sharp angles that are prone to cracking under stress. The drive end's beveled edge helps guide a ratchet tang smoothly onto the socket. The patented twist-to-lock rail system organizes and securely holds sockets in place―both for in your toolbox and on the go. A quick twist of the socket locks it onto the rail so that it can't fall off.

12-point opening fits double hex (12-sided)， hex， and square-shaped fasteners

Socket geometry is designed to apply force to flat sides of fasteners and not the corners， preventing round-off

Standard-length socket is relatively versatile and suitable for a wide range of applications

Extra-large die-stamped size markings are easy to read and can't wear off

Polished， chrome-plated finish easily wipes clean and is highly resistant to corrosion

Four detent grooves provide a secure connection with the drive tool

Beveled inner rim of the socket opening helps guide it smoothly onto fasteners

15-pc. 3/8 in. drive 12-point sockets: 1/4， 9/32， 5/16， 11/32， 3/8， 7/16， 1/2， 9/16， 5/8， 11/16， 3/4， 13/16， 7/8， 15/16， 1 in.

Includes socket rail