Review on Curt 40099: Heavy-Duty Chrome European Trailer Hitch Ball - 1,600 kg, 50mm Diameter, 3/4-Inch x 50mm Shank by Don Santos

The 50mm ball is very close in size to a US 2 inch ball. The main difference is the part of the stem under the bullet. On euro balls it is flat so you can bolt on accessories like towbar mounts and bike mounts. It's hard to tell from the photos that accompany the product, but this bullet has a flat shaft. If you had a European clutch your accessory will work with this ball. My only fault is that there is no way to put the key on it, so tightening the ball retainer is harder than it could be. I had to hold channel locks.