Shakespeare Style 4188-SL. RATCHET RAIL MOUNT STAINLESS STEEL. Ratchet action, fast release design for quick and easy laydown. Mounts easily on 1" to 1-1/2" vertical or horizontal rails. Standard 1"-14 thread.. 9/32" hole for cable feed-through. Handles antennas up to 8'. Standard 1" - 14 Thread. Stainless Steel, heavy duty construction. Heavy duty construction