Wrenches are tools used for gripping and turning objects such as pipe and fasteners. The wrench is placed around an object and then rotated to either tighten or loosen the fastener. Box-end wrenches have an enclosed head end that fits around the entire head of the fastener for a more secure grip while turning. Combination wrenches have an open end on one side and a box end on the other side that are used to turn a fastener. Crowfoot wrenches are open end style that can access fasteners in tight spaces, while flare nut wrenches have an opening in the wrench head that allows a brake line or obstruction to pass through it. Pipe wrenches are used to turn threaded pipe and pipe fittings. Strap wrenches can grip and turn round or cylindrical items, while chain wrenches use a length of chain to hold smooth, circular objects. Torque wrenches allow for a specific amount of force to be applied to a fastener so that it is not damaged by overtorquing.