Features:This steel shaft sleeve adapts a crankshaft from 5 or 8 inch to 3 or 4 inch diameter, it comes with 3 or 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 or 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 percent Brand NewItem Name: 5 or 8 inch to 3 or 4 inch Crank Shaft Sleeve AdapterMaterial: SteelColor: SilverSleeve Inside Diameter: 5 or 8 inchSleeve Outside Diameter 3 or 4 inchSleeve Length: about 3 inchSleeve Keyway Slot: 3 or 16 inchPackage Weight: approx.60gPackage List:1 x 5 or 8 inch to 3 or 4 inch Crank Shaft Sleeve Adapter1 x Keystock