Allow Two Speeds: Our PTO slip clutch limits the amount of torque being transferred from the tractor to the implement. This is accomplished by slipping or spinning free, which allows the two sides of the PTO shaft to spin at different speeds Quality PTO Slip Clutch: The 20CrMnTi carburized steel which built this tractor PTO slip clutch has been reinforced to resist impact. The black-painted surface is smooth and anti-weary. So, it can withstand higher torque and speed to gain better protection for your PTO shaft. 1 3/8' Round Shaft Ends: Constructed with Round ends, this PTO clutch has a standard size of 1-3/8' for both male and female ends. It perfectly matches the same diameter of implement input shaft and tractor output shaft, featuring superior safety functions as shear bolts. Easy Torque Adjustments: Rated torque: 900 nm, adjustment range: 20 - 55 hp. You can adjust the length of the tension springs to acquire an appropriate torque for your rotary cutter slip clutch