a lock - nut wrench has an elongated handle and a head at one or both ends of the handle . the head or heads have right and left arcuate jaws with distal ends that define a gap and each jaw has a first radially inwardly directed tooth at its distal end and a second radially inwardly directed tooth spaced proximally from it , defining spaces to accommodate diametrically opposed lugs . an offset can join each head to the handle . the inside of the head , that is , the inside of the jaws proximal of the second teeth , define a cylindrical surface that matches the radial outer extent of the lock nut lugs . the wrench can operate as a spanner , and can accommodate either a six - or an eight - lug lock nut . the handle is coated with an insulating plastic material . the ends of the jaws can be snubbed or hog - nosed . the wrench head may be adapted for use with a socket wrench handle . the wrench can be formed by laser - machining sheet or plate metal stock .