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