The hitch ball mounts to the ball mount or the weight distributing head. Hitch balls are available in Zinc, Chrome & Stainless Steel in the different sizes below. Keep in mind the hitch ball weight rating should always be equal to or larger than the hitch and ball mount being used. **Size Differences ** 1-7/8" balls have ratings up to 2000 lbs with a ¾" shank size 1-7/8" balls have ratings up to 2000 lbs with a 1" shank size 2" hitch ball has ratings up to 3500 lbs. with a ¾" shank size 2" hitch ball has ratings up to 6000 lbs. with a 1" shank size 2" hitch ball has ratings up to 8000 lbs. with a 1-1/4" shank size 2-5/16" hitch ball has ratings up to 6000 with a 1" shank size 2-5/16" hitch ball has ratings up to 14,000 with a 1-1/4" shank size