Attaches to a ratchet to tighten and loosens nuts and bolts
Also works with torque wrenches and breaker bars.
Available in standard (SAE) and metric sizes; some are color-coded to help you quickly distinguish between the two types.
Fits either a 1/4-inch, 1/2-inch or 3/4-inch ratchet; smaller sizes fit smaller fasteners, while larger fasteners usually need sockets with larger drive sizes.
Shallow, low-profile sockets fit spaces where there's little clearance above the head of the fastener.
Deep sockets can reach the nut on a longer, threaded bolt; they also allow you to reach recessed fasteners.
6-point sockets and 12-point sockets are available to fit a variety of fastener heads; universal sockets work with more fastener types, including spline, star and square.
Flex or flexible sockets have a built-in joint that allows you to use the handle at different angles, which is a useful feature in tight spaces.