Abstract: A ratcheting, open-end wrench concurrently engages more than half the corners of a nub during torquing. In preferred embodiments a wrench has a contacting cavity for receiving and torquing a nut, bolt head or other angularized nub. A chain carries a plurality of teeth about the inner perimeter of the cavity, and the chain is ratcheted so that the teeth move readily in one direction, but can be blocked from moving in the opposite direction. The teeth are arranged on the chain such that the cavity changes shape from an open configuration in which the nub can be received into the cavity, and a closed configuration in which the nub is locked into the cavity.