The 55mm Leather Ball Weight is made out of a VERY soft leather for your comfort and weighs about 13 ozs. The Weight is filled with small BB style weights that will help stretch, and may give you a great message, too. Because it is BB's it also is very comfortable because it will mold to any shape. They are about 1 1/4 or 1 1/2 inch inside diameter depending on which snap you use. The ends just snap together. Your boys are sure to be noticed more with these on.