The RAM Torque small rail base features a B size 25.4mm rubber ball and accommodates rails from 9.52mm to 15.87mm in diameter. Sizing inserts are included to provide a snug fit and protection of the rail. The mount utilizes nylon-insert locknuts to prevent loosening in high vibration environments. The RAM Torque small rail base allows for mounting to scooter mirror rails as well as vehicle headrests and other round rails within the stated dimensions. It’s made of powder-coated, marine-grade aluminium for durability and reliability in the most demanding environments