Made of 45 steel, which is environmentally friendly, strong and durable for long-term use. The universal joint can change the transmission direction at any angle. With perfect workmanship and precise size, the gasket is easy and convenient to install and remove. Suitable for straight shaft motors, use for toy cars, model boats, robots and other types of metal transfer. Contents: 1 universal joint.Features: Top quality. This joint or coupling connects rigid rods whose axes are inclined towards each other. Made of premium metal, it is durable and has a long service life. It is commonly used for shafts that transmit rotary motion. Widely used to connect toy cars, toy ships, robots, etc. Features: Material: 45 steel (exquisite plating). Inner Diameter: 2 x 2mm, 2 x 2.3mm, 2.3 x 2.3mm, 2 x 3mm, 2 x 4mm, 2.3 x 3mm, 2.3 > 4 x 5mm, 4 x 6mm, 5 x 5mm, 5 x 6mm, 6 x 6mm, 5 x 8mm, 6 x 8mm, 8 x 10mm , 10 x 10mm. (Optional) 2.3-2.3, 2 x 2.3, 2-2 outer diameter 8mm, length 18mm, weight about 8g, side fixed hole for M3. 2.3-3, 3 x 3, 3 x 3.17, 3.17 x 3.17 outside diameter 9mm, length 23mm, weight about 8g, fixed side hole for M3. 3.175-4, 4-3, 4-4, 4 x 2.3 outside diameter 9mm, length 23mm, weight about 8g, fixed side hole for M3. 5-4, 3-5, 5-5, 4-6, 5-6, 5-6, 6-6 outer diameter 11mm, length 23mm, weight about 10g, fixed side hole for the M4. 5-8 6-8 8 x 8 outer diameter 14mm, length 35mm, weight about 20g, fixed side hole for M4. 8 x 10, 10 x 10 outer diameter 16mm, length 35mm, weight about 28g, side fixed hole for M4. Content: 1universal joint (with set screw).