TheChainGang Donut Ball Stretcher Weight, Two Piece Surgical Steel Ball Stretchers Weights (30mm x 32mm 1 Pound 1 Ounces)

Bought the 32 mm, but they were too tight around the sack. Be sure you don't pick a size too small. My fault, bought 40 mm and they are far more comfortable. My fingers wrapped as an ok was 30 mm and I found the 40 mm size right. They are comfortable to wear and interesting to hide under tight jeans.