D-Ball American-Made Medicine Balls - The "Original" Slam Ball - D-Ball can make the claim to be the pioneer of the modern slam ball as we know it today with its original design of non-bouncing medicine ball, and for proudly being the manufacturer of the ONLY slam ball MADE IN THE USA! D-Ball uses flexible polyvinyl chloride (PVC), instead of rubber like most others, that goes through a unique rotational molding process. Each D-Ball slammer ball has a wall thickness of 3/8" no matter the diameter, as compared to 1/8" standard to most other core training balls in the industry. D-Ball has designed the toughest, thickest, most durable slam ball on the planet, designed to be thrown on any surface with as much force as possible. The fact that the D-Ball does not bounce creates additional workload during slam ball exercises as it must be picked up off the ground each time it is thrown down! D-Ball uses a proprietary mixture of 6-7 fill materials inside so that each strength ball will have a consistent feel no matter the weight or exercise with no "slosh" effect. By merely changing the composition of the fill material, D-Ball can vary the weight dramatically from very light to super heavy (using USA-manufactured steel shot as a heavy metal filler), all the while remaining consistent within a single diameter size as chosen. D-Balls experience no clumping and no hardening due to the mix of fillers used. A vent hole in the ball plug allows each ball to adjust to atmospheric conditions such as heat, cold, air pressure, and altitude. No matter where the med balls are used, or whatever the temperature, the soft feel will remain constant. Warranty: 1 Year for institutional use / 2 Years for individual use.