Check the listing for details. Demco HD A-frame Coupler 2-5/16" Bolt-on 21K Capacity EZ-Latch w/Chain Hooks. Condition: New. Listed at 172.89 USD. A coupler is the connection point mounted on the trailer which connects the trailer to the vehicle. When replacing a coupler there a few things that you have to know. First, what is the hitch ball size for the coupler. Secondly, what type of trailer do you have (Straight Tongue or A-Frame)? Lastly, what is the Gross Trailer Weight of the Trailer. These are the basic questions for finding the correct coupler replacement. Demco couplers are of the highest quality steel construction featuring: Adjustable lock nut for proper ball tension, locking hole in coupler handle and positive locking trigger. This Demco coupler is a heavy duty a-frame coupler that fits a 2-5/16" ball and has a GTW of 21,000lbs, perfect for your towing needs. This coupler also comes with chain hooks ans pre-drilled jack hole. Designed for 50 degree A-frame trailer tonguesBall Size: 2-5/16"Capacity: 21,000lbsSilver powder coat finish for resistance to corrosionDemco's exclusive EZ-Latch coupler design locks when dropped onto the hitch ballSafety chain anchors are 1/2 inch threaded