Pre-charged dampener unit, eliminates "pumping" before bleeding the brakes 2" coupler in closed position will auto latch on the hitch ball. Larger fill cap on master cylinder, easy to remove, easier to add brake fluid. DISC Brake models have solenoid plumbing built into the master cylinder. Standard length actuator cover. Cast steel ball clamp and latch handle. Stainless steel safety pin. Aluminum master cylinder. Coiled E-stop cable, PVC coated Grease fittings on roller pins.