Item: 8x8 D20L25 BF Series Aluminium Polyurethane Flexible Coupling Shaft Coupler Encoder CNC Stepper Motor d1xd2 : 8x8 mm Outer Diameter:20 mm Length:25 mm Body Material : Aluminum Alloy Sleeve Material:Polyurethane Pls kindly note: here's 5 pcs/lot. If you desire to buy other length which the products isn't always in our store pls contact us; Special Bre Size And Slot Available On Request. Delivery: The items will be sent for your address. Please make sure your address is correct. Feedback: We sincerely present nice merchandise and ideal service, so when you are satisfied with us, please go away your positive feedback, customers pleasure and supportive is our greatest return If there is anything that you are not satisfied with our item, please tell us so we are able to assist solve the problems. Please don't leave a damaging feedback. Thank you so much.