Precision molded composite "low ratio" pulleys (18T) and side plate for use on solid central layShaft. Set of 2 pulleys and 1 side plate. The teeth number (18) is embossed into the side of each pulley for easy identification. These low-ratio pulleys are for use only with other "low ratio" pulleys (1.77 ratio) and cannot be used with original ratio pulleys (2.125 ratio). These low-ratio pulleys also come as part of the Low Ratio Pulley Set."