Hyperwear Fit Ruck Convertible Sandbag Training Rucksack Back Pack for Sandbag Exercise Ultimate sandbag training versatility in a super sandbag backpack for Strength Training Outdoors Simply load it up, strap it on your back and head outdoors to start your rucking workout Rucking: the FIT RUCK is designed to carry up to 20 lbs of Hyperwear SandBells or Hyperwear SteelBells (sold separately) Convertible, patented, ultimate sandbag training tool has multiple handles SandBell (sold separately) filler sandbag weights give you unlimited exercise options