A Gun Coupler is holding equipment that used for the easy lubricating process. If you have a car, truck, or any equipment farm you know lubricating is essential for this type of equipment. The coupler is used to grease boat trailer bearings. The coupler is made from polymer and is designed to handle all kinds of damage and extreme temperatures. The Coupler is made for use in the various places. The Gun Coupler is easy to use and made for long term use.