The BCS Curved Coupler easily slides onto the tractor's hitch, which is located just above the PTO on models 718 and up. The accessory is required to stabilize and balance the tractor when using tow-behind attachments, most notably the Utility Trailer. It fits onto the tow hitch and is fastened by sliding a pin through the coupler and hitch. This configuration allows the towed implements to rotate side-to-side, but not up and down. The Curved Coupler comes in two sizes: one for models 718 - 739, and one for models 749 and up. This is because the tow hitches are smaller up to 739 and wider for models 749 and 853. Model 750 can not accommodate the Curved Coupler with a 33'' Tiller attached.