The Klein Tools NRHD3 Single-Ended Impact Socket features three square socket sizes in one socket to save time. This unit includes 3/4 in., 1 in. and 1-1/8 in. square socket sizes, plus a 7/16 in. hex quick-change adapter. The Klein Tools NRHD3 features a hollow shaft that allows for use on long threaded bolts. Users can extend or retract the head for easy access to the size they need.