A Crescent Wrench, or C Wrench, is a trade name for an adjustable angle head wrench. The Crescent Wrench is made by Cooper Hand Tools, however many companies make very similar adjustable wrenches. The wrench is mainly used in electrics, or the lighting department, for hanging of lighting fixtures. The standard sizes used are the 6" or the 8". (Many union calls and theatre departments will only allow the use of a 6" to prevent over tightening of the bolts on the lighting fixtures or clamps) With the adjustable wrench, a screw type adjustment can be made on the handle of the tool, allowing the jaw to open or close, thus allowing the wrench to grip different sized nuts and bolts.