UNIFORM SIZE All Power Systems Wall Balls are 14 diameter, regardless of weight. The consistent, large size helps you train from lighter weights to heavy ones, with correct form. This consistent diameter and design helps you maintain neutral spine to increase stability and max power at any weight. WIDE SIZE RANGE Train your way to stronger with any of the 10 weight options, 6,8,10,12,14,16,18,20,25, or 30 lb. weights. DURABLE BLACK VINYL SHELL is scuff-resistant, moisture resistant and smooth and comfortable to hold and catch. The shell is strong enough for high impact and high-speed training. INTERNALLY REINFORCED TO MAINTAIN SHAPE the weighted core, padding and internal stitching allows you to throw the Power Systems Wall Ball at a high velocity without risk of injury, and helps the ball retain its shape after heavy use.