Spring-loaded 'X' design with rubber caps sports great holding power without hiding your phone; includes optional device tether for peace of mind during rugged use Includes U-bolt base that accommodates rails from .5" to 1.25" in diameter and a short length B size RAM double socket arm; ball and socket technology allows for near-infinite adjustability Device Holder Dimensions: Width Range: 1.875" - 3.25" Depth Range: .875" max; Clamp Range: .5" - 1.25" diameter Made of powder-coated, marine-grade aluminum, stainless steel components, and high-strength composite for durability and reliability in the most demanding environments Backed by a lifetime warranty