Specification Brand : Aicosineg BulletPoint1 : Outer Diameter: 9mm/0.35 inch;Length: 23mm/0.91 inch. BulletPoint2 : Inner Hole Dia : 5mm x 5mm/0.20 inch x 0.20 inch ; Thread Size: M4. BulletPoint3 : Provides torque transmision and alignment,Cost effective coupling design,which is very flexible and easy for use. BulletPoint4 : High quality material: The universal joint coupling nuts are made of premium material, which is sturdy and durable for long lasting use. BulletPoint5 : Application: The rotable coupling is perfectly applicable for RC model car and RC model boat,is perfect motor shaft fitting accessories. ExteriorFinish : Nickel ExternallyAssignedProductIdentifier : 9406092481054 ItemName : 2Pcs 5mm to 5mm Inner Dia Rotatable Universal Steering Shaft U Joint Coupler L23 x D9,Aicosineg ItemPackageDimensions_Height : 5 centimeters ItemPackageDimensions_Length : 5 centimeters ItemPackageDimensions_Width : 5 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : pin-and-block-universal-joints Manufacturer : Aicosineg Material : Iron Material1 : Nickel Material2 : Iron MetalType1 : Nickel MetalType2 : Iron NumberOfItems : 1 PartNumber : EF069000KAI10-FBA ProductDescription : Provides torque transmision and alignment. Cost effective coupling design. Nickel-coated Iron is good in corrosive environments. Ideal accessories for RC Model motor, such as airplane boat model.