1、It can change the motor of different diameter shafts and change the belt pulleys of different speeds. 2、It reduces the need to purchase new motors or pulleys to maintain existing components and speed/power requirements. 3、Adapt the larger wheel hole to the small shaft and work with the pneumatic crank shaft. 4、Increase the crank diameter to accommodate pulleys, gearboxes, etc. 5、The inner diameter of the sleeve is 5/8inch, the outer diameter of the sleeve is 3/4inch, the shaft length is about 3inch, and the sleeve key groove is 3/16inch. Features: It can change the motor of different diameter shafts and change the belt pulleys of different speeds. It reduces the need to purchase new motors or pulleys to maintain existing components and speed/power requirements. Adapt the larger wheel hole to the small shaft and work with the pneumatic crank shaft. Increase the crank diameter to accommodate pulleys, gearboxes, etc. The inner diameter of the sleeve is 5/8inch, the outer diameter of the sleeve is 3/4inch, the shaft length is about 3inch, and the sleeve key groove is 3/16inch. The sleeve and key holder are designed to fit snugly over your 5/8inch diameter crankshaft with a 3/16inch keyway and extend to 3/4inch diameter with a 3/16inch key holder. Specifications: Condition: Brand New Material: Aluminum alloy Color: Shown as picture Package List: 1 * Round Shaft 1 * Long Key