To protect power-transmission components from damage, these couplings will shear or tear in overtorque conditions (approximately 10-20 times the maximum rated torque) to sever connections between shafts. They have a flexible center that not only compensates for misalignment, but also dampens vibration and shock loads. Couplings have no metal-on-metal contact, reducing noise and eliminating the need for lubrication. Fasten to your shaft by tightening the set screws, which bite into the shaft to hold it.