RAM Mount Torque 0.375" to 0.625" Mini Handlebar Rail Base w/ 1" BallThe RAM Torque bar mount has a 1 rubber ball and accommodates rails 3 8 to 5 8 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 B 408 37 62U allows for mounting to scooter mirror rails as well as vehicle headrests and other round rails within the stated dimensions.