Attwood Corp LightArmor Plug-in Base Boat Trailer Accessory - The new Light Armor Plug-In Light Bases have a threaded design feature that fits perfectly with the threaded locking collar now offered across the entire line of Attwood Pole Lights. This unique system ensures a tight and secure fit that prevents annoying rattling while underway or trailering Threaded Locking System for a secure fit Unique cover design Stays secure while underway or trailered Low-profile prevents water from pooling on top surface