Find both SAE and metric box-end wrenches at Grainger. Use a box-end wrench, which features thin sides and a closed end that encircles fasteners, to help turn nuts that are hard to reach. Half-moon wrenches can work well for automotive repair or other mechanical work where an obstruction may make the fasteners hard to reach. Use a non-sparking box wrench in potentially explosive atmospheres and insulated box wrenches where there could be danger of electrical shock. Let Grainger fix you up with durable, rugged box-end wrenches!