Using proven Vise-Grip technology， this tool locks on 3 sides of a hex head fastener. Tremendous force can be applied without damaging or slipping off the fastener. Helps eliminate rounding of head caused by slippage. Locking wrench adjusts to a range of standard and metric wrench sizes. Wrench has wire cutter and knurled jaw tips. Carded. 7"， adjusts from 7/16" (11mm) to 3/4" (19mm).