The RVGC Gooseneck Coupler is a product that will allow you to pull your 5th wheel camper with a Gooseneck ball without having to bolt on an adapter. This is a one piece product that bolts onto your existing bolt holes where your king pin box is mounted. Simply unbolt your existing king pin box and install the RVGC in the same bolt holes. This product is rated at 24, 000 lbs. and a tongue weight rating of 6, 500 pounds. The RVGC-A is the adjustable version which gives you 4" of adjustment down by the coupler and most trailer manufacturers have adjustable whole patterns to allow you an extra 3″ of adjustment. Which makes the total about 7" of adjustment. Bolt hole location and number of holes will vary depending on the configuration of your current pin box model. The number of holes, and size of holes are specific to the pin box model currently on your unit.