Features: 100% brand new and high quality Dimensions: 14 x 25mm/0.55 x 0.98"(outer diamater x length). Compatible with 42mm stepper motors. Remove stress when shafts are not aligned perfectly. Connecting two axis with different diameters, can also be connected with a motor axis, or connecting shafts of different diameters. Suitable for 3D printers, motor couplings, boat models, car models, airplane models, etc. Package Includes: 1 x 3D Printer Motor Coupling Specifications: Interface Size:approx 5x5mm / 5x8mm / 6x8mm / 8x8mm Material: Aluminum Alloy Quantity:1pc Color: Blue for :42mm Stepper Motor(3D Printer) note: Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to the manual measurment.