RAM Mounts RAM-B-149Z-A-PD4U Quick-Grip XL with U-Bolt Short ArmHeavy duty spring loaded phone mount for handlebars & rails The RAM B 149Z A PD4U Quick Grip XL phone mount combines RAMs rugged spring loaded cradle with a handlebar U Bolt base and short arm to give you a secure, adjustable mount on handlebars, rails or tubes that measure between 0. 50 and 1. 25 diameter. Perfect for keeping your device in view on bikes, UTVs, e bikes, ATVs and other outdoor rigs where vibration and movement are part of the ride.