1Function: Shaft couplers are used to hold bearings and sprockets tightly on the shaft, and are used in motors, hardware, molds, mechanical transmission occasions. 2Practical: The flexible design of the coupling effectively eliminates the stress between the motor and the drive components, making the motor run faster and more efficiently. 3Durable Material: The shaft coupler connector is made of steel material, which has high strength, wear resistant and durable for corrosion resistance and enhanced durability. 4Important Parameter: Length is approx. 22mm/0.87in, outer diameter is approx. 14mm/0.55in, inner diameter is approx. 6?8mm/0.24?0.31in, side aperture is approx. 4mm/0.16in. 5Easy Installation: Easy to install, the extra fixing screws will save you the trouble of drilling extra holes and be safer when operation.