【Description:】 Motor Shaft Rigid Brass Sleeve Coupling offer high torque, stiffness, low inertia and excellent sensitivity ,you can use them for a long time.Steel shafts give a combination of hardness and toughness for wear resistance 【Specification of Coupling：】 Material: quality brass； Connection Bore Diameter: 7mm-7mm(0.28"-0.28")； Total Length: 22mm /0.87"； Outside Diameter : 16mm/0.63"； Parameters: Bore size of your choice Bore Tolerance + 0.03； Screw Thread Size: M4； 【Specification of Steel shaft：】 Material: Steel； Diameter: 7mm(0.28") ； Length: 100mm(3.94")； 【Application:】Special shaft for coupling is used for extension of transmission shaft. 【Package:】1x Motor Shaft Rigid Brass Sleeve Coupling，1 x Allen Wrench ，4 x Screws，1 x Steel shaft 【Guarantee：】Contact us if you encounter any product problems. We will provide suggestions or even refund services for products with quality problems.Welcome to click "Contact Seller". Send us an email and we will customize it for you.