The large version of the RAM® Torque™ handlebar mounting base features a 1" / 2.54cm / 2.54cm B size RAM® rubber ball and is compatible with rails 1 1/8” to 1 1/2" / 1.27cm / 1.27cm in diameter. Sizing inserts are included to provide a tight fit while also protecting the mounting surface. The large RAM® Torque™ mounting base also includes nylon-insert lock nuts to prevent loosening in high vibration environments.