The box end of the wrench has a closed loop with six or twelve points (depending on the model) designed to fit the corresponding sides of a nut or bolt head. The ratchet mechanism allows the wrench to turn the fastener in one direction while allowing it to rotate freely in the opposite direction without having to remove and reposition the wrench.
This ratchet box wrench is especially useful in small or confined spaces where there isn't enough room to wiggle a traditional wrench. Ratcheting socket wrenches come in a variety of sizes and configurations to accommodate different nut and bolt sizes and are widely used in automotive repair, machine maintenance, plumbing and other mechanical applications.