Bulldog trailer couplers are the standard by which all others are measured. No other competitor offers the combination of Heavy-Duty materials unique features and replaceable parts for outstanding performance and long life. That’s why Bulldog is the right selection for your Heavy-Duty towing needs whether its utility hauling horses and livestock cargo or construction trailer applications. Bulldog is the most trusted name in trailer couplers and our adjustable trailer couplers are no exception. For over 80 years Bulldog has been building that reputation with a number of innovations that have enabled it to stay out in front of the completion. Designed for the most rugged applications like horse and livestock hauling utility hauling and construction trailer use these couplers are the strongest in the industry. The Bulldog adjustable height coupler is available in either a Wedge Latch® style or Channel Mount style. The Wedge Latch® adjustable height coupler features patented coupler technology for positive secure locking. An (optional) available height channel bracket allows the selection of up to five height settings ensuring a perfect match to the trailer height for safe and secure towing. Trailer Coupler Adjustable Lock Nut For Proper Ball Tension Locking Hole In Coupler Handle. Quick And Easy To Engage Positive Locking Trigger. Strong And Secure On The Road Patented Wedge Latch® Ball Clamp Design Quick To Hook Up And Disconnect. In Compliance With SAE Standard J684