The rear-view mirror frame features a 1-inch (2.5 cm) ball holder base compatible with mirror rods having diameters from 0.39 inches (1.0 cm) to 0.63 inches (1.6 cm). The circular rail adapter for motorcycle rearview mirrors and mini handlebars includes three sizes of rubber ring inserts for secure fit and surface protection. Rubber ring pad diameters: 0.5 inch, 0.87 inch, and 1 inch. The aluminum alloy mounting base uses rubber inserts and locking mechanisms to resist loosening caused by vibration. It is designed for installation on rearview mirror frames, motorcycle and bicycle mini handlebars, and other circular rails within the specified size range. This 2.54 cm ball seat is constructed from 6061-T6 aluminum alloy for durability in demanding conditions. The ball features TPU molding for enhanced grip. The 1-inch (2.5 cm) tee base is compatible with RAM mounting systems, dual socket arms, and other accessories using a 1-inch tee configuration. Suitable for bicycles, motorcycles, mountain bikes, electric scooters, and ATVs. Color: Black Material: Aluminum alloy + plastic Package Contents: 1 × Navigation mounting bracket Note: Color appearance may vary slightly due to lighting and display settings. Measurement tolerance: ±1–3 cm.