Couplers
All couplers are not created equal.Comparing the Atwood and Demco for example, Demco offers a rebuild kit for the cylinder, Atwood does not. The cylinder is made of composite materiel so it won't rust, I think the Atwood continues to use a cast iron cylinder. It has a built up boss for the fill plug to resist water infiltration, the Atwood has a flat plate.The fill plug has a bladder to close the system to avoid contamination of the brake fluid by either immersion or attracting water from the air, the Atwood has a vented cap.I'd seriously consider the Demco over the Atwood unless Atwood has made recent changes.I agree, Champion Trailers are very good folks to do business with.My last suggestion, if your redoing the coupler, redo the brake cylinders at the same time. Purge the lines with air pressure and go back with Dot 5 synthetic fluid rather than standard fluid which attracts moisture.If you stay with the cheaper dot 3 fluid, be sure to purge it yearly and refill with fresh fluid, once it draws water from the air... it will rust the wheel cylinders and surge cylinder also if its cast iron. A little rust is all it takes to destroy the seals of the cups and produce a leaky sticky brake system.