Features: 1.It is made of high?quality metal materials, strong and durable, and has a long service life. 2.The original factory standard configuration, the old or broken ones can be replaced directly. 3.This steel shaft sleeve adapts a crankshaft from 3/4in to 1in diameter. It comes with step key that offsets from 3/16in to 1/4in. 4.Reduces the necessity of buying a new motor or pulley to maintain existing components and speed/power Requirements. 5.The installation is simple, no complicated tools are needed, and it is easy to use. Specification: Item Type: Engine Pulley Crank Shaft Sleeve Adapter Material: Stainless steel Sleeve Inside Diameter: 3/4in Sleeve Outside Diameter: 1in Sleeve Length: About 3in Sleeve Keyway Slot: 1/4in Step Key Length: About 2in Function: 1. This steel shaft sleeve adapts a crankshaft from 3/4in to 1in diameter. It comes with step key that offsets from 3/16in to 1/4in 2. Alters motors with a different diameter shaft 3. Alters pulleys for a different speed or belt 4. Reduces the necessity of buying a new motor or pulley to maintain existing components and speed/power Requirements. 5. Adapts larger wheel bores to smaller axels 6. Works with Gas Engine Crank Shafts to enlarge the crank diameter to fit pulleys, gear boxes etc.