With features such as corrosion resistance, rust resistance, wear resistance and high hardness, this product can withstand harsh environments and be used for a long time. By using this product, you can mount your tail light or camera on the back of your bike seat post, making it convenient and providing safety for your night rides. It is made of high-quality plastic and aluminum alloy material. Style A is suitable for bicycle seatpost diameter of 25.2-31.8mm, and style B is suitable for bicycle seatpost diameter of 30-32mm. It is suitable for Garmin Varia taillight. Item Name: Seat-Post Mount Material: Plastic, Aluminum Alloy Features: Multifunction, Easy to Install, Wide Compatibility Size Details: Style A Size, Suitable Seatpost Diameter: 2.52cm-3.18cm/0.99"-1.25" (Approx.) Style B Size, Suitable Seatpost Diameter: 3cm-3.2cm/1.18"-1.26" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: Style A: 1 x Seat-Post Mount 2 x Ring Gasket 2 x Spare Screws 1 x Hex Wrench or Style B: 1 x Seat-Post Mount 2 x Rubber Pads 2 x Hex Wrenches