Specification Brand : Vgoohobby BulletPoint1 : Ideal for RC Model motor,widely used in model shaft connection.compatible with RC DIY Airplane Boat Robot. BulletPoint2 : Made of high quality brass,durable in use.A variety of sizes available to be chosen. BulletPoint3 : Inner Diameter: (Size Optional) 2mm-2mm/3mm-3mm/3mm-4mm/3mm-5mm/3mm-6mm/3.17mm-3.17mm/4mm-5mm/5mm-5mm/6mm-6mm BulletPoint4 : Outer Diameter: 9mm. Height: 20mm BulletPoint5 : Pack of 6Pcs,with Screws.Well made,a good Compatible with your old or broken one. Color : Gold ConnectorType : Coupling DriveSystem : External Hex ExteriorFinish : Brass ExternallyAssignedProductIdentifier1 : 048518401209 ExternallyAssignedProductIdentifier2 : 0048518401209 FinishType : Brass ItemName : 6Pack Vgoohobby Brass Motor Shaft Coupling Coupler Connector Sleeve Joint Adapter for RC DIY Airplane Boat Robot (2mm to 2mm) ItemPackageDimensions_Height : 6.7 centimeters ItemPackageDimensions_Length : 0.7 centimeters ItemPackageDimensions_Width : 4.8 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : set-screw-couplings Manufacturer : Vgoohobby Material : Brass Material1 : Copper Material2 : Brass MeasurementSystem : Metric MeasurementSystem1 : Metric MeasurementSystem2 : Inch MetalType : Alloy Steel MetalType1 : Copper MetalType2 : Brass ModelNumber : XZ121 NumberOfItems : 1 NumberOfPieces : 6 PartNumber : XZ121 ProductDescription : Item Name : Motor Shaft Coupling; Ideal for RC Model motor,widely used in model shaft connection.compatible with RC DIY Airplane Boat Robot. Made of high quality brass,durable in use. Well made,a good Compatible with your old or broken one. Easy to install and remove. A variety of sizes available to be chosen