Features: brand new and high quality The screw diameter of the bicycle tail is 4.8 for cm. Please check the diameter of the screws at the end of the bicycle. Good corrosion resistance, high toughness, no deformation after long-term use. Easy to install, with high strength and high performance. Only the bicycle extension bracket set, does not include the other accessory demonstration in the picture. The installation is simple, easy to carry, and the ride is firm and not easy to fall off. Specifications: Material: Aluminum Alloy Size: Approx.8x4.2x2cm/3.14x1.65x0.78in Color: Black, Red(Optional) Note: Please allow 1-2cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 Set Bike Code Table for Seat