The RAM® X-Grip® Large Phone Mount with RAM® Vibe-Safe™ & U-bolt Base - Short (RAM-B-149Z-A-UN10-462) / Medium (RAM-B-149Z-UN10-462) is a combination of the RAM® X-Grip® Large Phone Mount with Handlebar U-bolt Base and the RAM® Vibe-Safe™ - the vibration damping accessory is designed to protect electronic devices from a wide range of vibration frequencies. This product comes pre-assembled with the device tether that is recommended for outdoor applications. The RAM® X-Grip® can rotate between portrait and landscape by loosening the center screw. This product comes with one (1) short B size arm OR one (1) medium B size arm and one (1) RAM&erg; U-bolt Base that accommodates rails from 0.5" - 1.25" in diameter and an optional device tether that is recommended for outdoor applications. The holder is compatible with handheld devices that will fit the dimensions listed below, it is important to verify the dimensions of your handheld device with a case / sleeve / skin when determining the overall size. RAM® Vibe-Safe™ dampens a wide range of vibration frequencies. Made of high-strength composite and stainless steel hardware for durability and reliability in the most demanding environments. Unique structure and thoughtfully designed with all industries in mind. Backed by a lifetime warranty. Tech Specs: Hardware included: (1x) optional tether. (1x) glue tube for rubber caps. (1x) 1/4"-20 U-bolt for 0.5" - 1" rails. (1x) 1/4"-20 U-bolt for 1" - 1.25" rails. (2x) 1/4"-20 Nylock nuts. (2x) rubber caps. (1) U-bolt spacer. Holder dimensions: Width range: 1.75" - 4.5". Depth range: 0.875" maximum. Clamp range: 0.5" - 1.25" diameter. Socket-to-socket length: 1.75" (Short) / 3" (Medium). Ball size: B Size (1"). Weight capacity: Standard use: 2 pounds. Heavy-duty use: 1 pound. Materials: Marine-grade aluminum. High-strength composite. Stainless steel. Weight: 0.99 pounds (Small) / 1.07 pounds (Medium). Note: A reduction in vibration does not guarantee full protection of device. External immeasurable factors may cause damage to phones, cameras, and other devices while mounted in the RAM® Vibe-Safe™. National Products, Inc does not assume responsibility or liability for any such personal injury, death or property damage. RAM® mounts lifetime warranty is limited to RAM® mounts and components. The warranty does not include any device mounted or attached to a RAM® mount, such as a phone, GPS, camera, computer or other device.