14-inch diameter, durable vinyl soft-shell, moisture resistant

Those discount medicine balls your gym has sitting around are probably too small and yet too heavy for true velocity work. And most of them flatten like a gluten-free pancake every time they hit the ground. See, most medballs are under 10 inches in diameter. That's okay for some movements, but unnaturally narrow for others. All standard Dynamax balls are 14 inches, no matter the weight. That just feels right ergonomically. It probably has something to do with the natural "power position" of your body. Every Dynamax medball is handmade in America. The soft-shell is grippy and ridiculously durable. I've even used mine outdoors on rough terrain without a single tear. These things will absorb thousands of high-velocity impacts and retain their shape and balance.

– Chris Shugart