The Master Lock® Receiver/Coupler Lock Set features a 5/8" (16mm) stainless steel receiver lock and adjustable coupler latch lock. The receiver has a simple Push to Lock™ locking mechanism, while the Weather Tough® seal and water tight cap help protect against damage from moisture and dirt. The coupler latch lock adjusts from 9/16" (14mm) to 2-3/4" (70mm) to accommodate a variety of applications. Receiver/Coupler Lock Set, 1/2 and 5/8 In