Gronk Fitness 3-in-1 Soft-Sided Ballast Plyometrics Box. Get the MOST STABLE 20″, 24″ and 30″ tall plyobox, all in one. A Stable Plyo Box with a Shifting Low Centre of Gravity With the patent-pending WeightShift Technology, when the plyo box is turned, the ballast ‘flows’ to fill the lowest internal face of the inner plywood box. Now, you have a plyobox with optimal balance and stability, no matter which side/height you use. This virtually eliminates shifting and tilting of the plyo box while in use. This 3-in-1 Ballast Plyo Box is a staple item of any fitness studio or box. It allows you to customize your workout and adjust on the fly. This unmatched versatility removes clutter from your workout space. Simply rotate the plyo box to your desired height and jump. This item is soft and safe. With a reinforced wooden core, surrounded with a multi-layered foam covering, safety and durability are of crucial importance. The durable vinyl cover resists wear and tear while remaining firm even after heavy use. Never worry about footprints or dirt again, as the vinyl covering allows for easy cleanup. Special Features: Safest Plyo Box Available / Solid and Stable / 3 Ballast Balls in the Core / Durable Wood Interior Core / Multi-Layered Foam / Double Stitched Vinyl Upholstery / Resists Compression / 20ö, 24ö and 30ö Heights in One Plyo Box / Specifications: Ballast balls: .6″ diameter, 12lbs weight (x3) .6″ wooden board constructed core 3″ foam pad thickness Length: 30″ Width: 20″ Height: 24″ Plyometric exercises are perfect to improve an athletes ability and skill and will seriously increase speed and strength. Plyometrics will improve the ability of an athlete to start quicker, accelerate faster, change direction more quickly. A must have for all athletes to improve these functions. Comes Built. 77lbs