Ruland KM-12-12-FZ is a straight style key stock with 12mm height x 12mm width. The oversized tolerance provides a tight fit with the key slot on the shaft for zero-backlash power transmission. It is designed to be used with Ruland shaft collars and rigid couplings that have a 40mm bore size to allow for higher torque capabilities in the application and prevent slippage on the shaft. Ruland key stock is supplied in 12" (304.8 mm) lengths allowing the user to cut to size for their application. KM-12-12-FZ is made from high grade steel for high torque applications with a zinc plated finish for added corrosion resistance. It is US manufactured and RoHS complaint.