The Convert-A-Ball Super Duty Cushioned Ball Mount acts as a shock absorber and is effective in reducing bounce and rhythmic vibrations. This protects the towing vehicle's driveline, hitch assembly, and trailer contents. It fits 2.5" receiver hitches without an adapter sleeve. It is designed with a 1.25" hole for 1.25" diameter ball shanks. Smaller diameter shanks must be installed with an appropriate reducer bushing.