【45# Steel Material】: This shaft coupling is made of 100% brand new and high quality steel materials. This material is not easy to rust, corrosion resistant, durable and has a long service life. 【Size】: You will receive 5 * universal joints, 1 * hex wrench, 10 * set screws, Hole diameter: 3mm to 3mm / 0.12inch to 0.12inch 【Good Performance】: Compensation for axial and radial misalignment. Shock absorption, high transmission efficiency, noise reduction and low wear. 【Rigid Rod Connection】: This connection or coupling connects rigid rods whose axes are inclined to each other. The perfect workmanship and precise dimensions make it very convenient for you to use. 【Widely Used】: Metal universal joints are often used for short supporting shafts, straight shaft motors, model cars, ships, robots and other metal transmissions.