Metric Check Nut wrenches are made of steel and come in sizes from 1/2" to 1-11/16" in fractional size and 10mm to 41mm in metric size. They are used for servicing various types of nuts, including check nuts and stop nuts, and are available in an industrial black coating. These wrenches also come in smaller sizes for service purposes. (Also known as Thin Head Wrenches) They have a 15 degree angled slotted opening and are ideal for adjusting and lock nuts due to their thin head design. Made in the USA.