Features: *1. The bottom diameter of the product design is 8mm or 10mm, and the ball head diameter is 25mm, which is suitable for most models and brackets and is widely used to fix phone holders and sports cams *2. The ball head of the product is made of rubber, and the screw is made of stainless steel, which is durable and elegant in appearance *3. The screw of the product has a thread that can directly install the original rearview mirror or the position with screw holes, and the installation is convenient and quick *1. Material: Rubber+stainless steel *2. Ball Head Size: 25mm(M8), 25mm(M10) *3. Thread Length: 11mm(M8), 11mm(M10) *4. Pitch: 1.25mm(M8), 1.25mm(M10) *5. Bottom Diameter: 8mm(M8), 10mm(M10) *6. Total Length: 52mm(M8), 52mm(M10) *7. Thread Direction: clockwise *8. Packing Size: 10.8x6.7x2.6 cm Package Includes: 1 x Rail Mount Note: 1. All pictures have been professionally calibrated, but due to the ambient light and different display device settings, the pictures and items you see may have some deviations, please forgive me. 2. The data is manually measured, there may be some deviations, but it does not affect the use.