Universal Rail Clamping Base - The 1.5" ball clamp base securely clamps round, square, odd-shaped rails and bars from 1.18'' to 2'' in diameter. Widely used on boat, kayak, ATV, UTV, industrial truck and other vehicles. Perfectly fits 1.5 inches / C size / 38 mm arm systems, compatible with RAM Mounts, Arkon, iBolt and others. So Sturdy and Durable - Constructed from Marine-Grade Powder-Coated Aluminum and tested for thousands of hours in salt spray to ensure reliability and stability in the harshest environments. 1.5" Ball Made of Marine-Specific, High-Strength Composite Material, which is more resistant to high salt water corrosion and less prone to deformation than rubber. Provides the same friction as rubber. Wide Range of Applications - Great for phone mount, tablet mount, camera mount, marine electronic mounts, fish finder mounts, fishing rod holders, GPS chartplotter mounts and more. Ideal for mounting on handlebars of motorcycle/truck/bike/bicycle/golf cart/electric scooter/ATV, on rails of boats, kayaks, inflatables, on frames of UTV, industrial and agricultural vehicles, and even mounted on shelves. Great for tablet mount, camera mount, marine electronic mounts, fish finder mounts, fishing rod holders, GPS chartplotter mounts and more. Ideal for mounting on handlebars of motorcycle/truck/bike/bicycle/golf cart/electric scooter/ATV, on rails of boats, kayaks, inflatables, on frames of UTV, industrial and agricultural vehicles, and even mounted on shelves.