CNC machined from strong 7075-T6 aircraft-grade structural aluminum. 3.89″ W x 2.50″ H x  .75″ T. Threaded for a total of eight 5/16-18 screws for teeth. (Two teeth per side suggested). Bored and reamed for two Needle Roller Bearings which are installed. Two threaded holes for attaching 1.5 Inch Spinner Bar Pulley. usa