1、This steel shaft sleeve adapts a crankshaft from 5/8 inch to 3/4 inch diameter, it comes with 3/16 inch keystock. 2、Alters motors with a different diameter shaft and alters pulleys for a different speed or belt. 3、Reduces the necessity of buying a new motor or pulley to maintain existing components and speed/power requirements. 4、Adapts larger wheel bores to smaller axles, works with Gas Engine Crank Shafts to enlarge the crank diameter to fit pulleys, gear boxes etc. 5、One adapter and keystock included; Made from cold rolled steel, CNC precision machined and tumbled, high durability. Features: This steel shaft sleeve adapts a crankshaft from 5/8 inch to 3/4 inch diameter, it comes with 3/16 inch keystock. Alters motors with a different diameter shaft and alters pulleys for a different speed or belt. Reduces the necessity of buying a new motor or pulley to maintain existing components and speed/power requirements. Adapts larger wheel bores to smaller axles, works with Gas Engine Crank Shafts to enlarge the crank diameter to fit pulleys, gear boxes etc. One adapter and keystock included; Made from cold rolled steel, CNC precision machined and tumbled, high durability. Specification: Condition: 100% Brand New Item Name: 5/8 inch to 3/4 inch Crank Shaft Sleeve Adapter Material: Steel Color: Silver Sleeve Inside Diameter: 5/8 inch Sleeve Outside Diameter 3/4 inch Sleeve Length: about 3 inch Sleeve Keyway Slot: 3/16 inch Package Weight: approx.60g Package List: 1 * 5/8 inch to 3/4 inch Crank Shaft Sleeve Adapter 1 * Keystock