Specification Brand : uxcell BulletPoint1 : 【Type】- 8mm Hex Brass Shaft Coupling, suitable for model shaft connection, perfect accessories for RC Model motor, etc. BulletPoint2 : 【Coupling Size】- Hex Height : 6mm ; Opposite Side: 12mm ; Cylinder Height: 24mm ; Cylinder Outer Diameter: 11.5mm ; Cylinder Inner Diameter: 8mm ; Fastening Screw Hole: M4 BulletPoint3 : 【Material:】- Made of brass, sturdy, reliable and strictly functional. Durable and insulation, make your shaft more stable, easy to install and replace. BulletPoint4 : 【Function】- A special coupler, used for connecting the motor shaft and the hexagon wheel of the robot and other models. BulletPoint5 : 【Package Content】- 4pcs Hex Coupler, 8pcs M4 Screws, 2pcs 4mm Hex Wrench. DriveSystem : External Hex ExteriorFinish : Brass FinishType : Brass ItemName : uxcell Hex Coupler 8mm Bore Motor Hex Brass Shaft Coupling Connector for Car Wheels Tires Shaft Motor 4pcs ItemPackageDimensions_Height : 13.6906 centimeters ItemPackageDimensions_Length : 1.6002 centimeters ItemPackageDimensions_Width : 9.6012 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : power-rotary-tools Manufacturer : uxcell Material : Metal MetalType : Brass PartNumber : a19120400ux0060 ProductDescription : Description : 1.Material: Made of pure brass, sturdy, reliable and strictly functional. 2.Function: A special coupler, used for connecting the motor shaft and the hexagon wheel of the robot, cars, and other models. 3.Use: Suitable for model shaft connection, perfect accessories for RC Model motor, etc. 4.Feature: Durable and insulation, make your shaft more stable, easy to install and replace.