Tools Plus carries a wide range of square drive, clutch head, and spanner insert bits. The square drive bit, or Robertson bit, features a tapered square projection, which allows for easy one hand use and reduces "cam out". This bit type is common in Canada and Canadian manufactured automobiles. The spanner bit is used for screws commonly found on elevators that are designed to prevent tampering. A clutch head bit is used for screws regularly found on GM automobiles from the '40s and '50s, as well as mobile homes and recreational vehicles.