You gain two more square donuts with this expansion pack. Try buying a different color to create your own custom look. One expansion pack plus the original Boner Kit will give you four square donuts total. Features: Super stretchable yet firm TPR Stackable and compatible with the Boner Kit Material: Super stretchable yet firm TPR Dimensions Ball Ring Exterior: 1.3 by 1.3 in. Ball Ring Interior: .9 by .9 in.