If you like the idea of working out with water out of the water, check out these nifty Aqua water-filled boxing bags too. Both water weights allow over 50 different movement patterns - more if you're creative - and 3 grip options. Surge fitness tools come in Storm and Riptide models. The Storm is the original, larger option at 42" long and 8.5" in diameter. Empty it weighs 9 pounds, and filled to the brim with water 60.5 pounds. Surge Riptides are a more compact 33.25" long, and still 8.5" in diameter. Empty they weigh 7.5 pounds, and full 38 pounds. According to proponents of active resistance training, this type of exercise also better simulates activities and challenges you'll encounter outside the gym, in daily life, or during sports and recreational activities. The idea is that this forces you, and especially your core, to work harder to complete reps and maintain control over the Surge device. In other words, as you move, the water will too. Part of the "active resistance training" camp, these sandbag-shaped, slosh-pipe-inspired rigid weights are filled with water - your choice how much - so that during use their weight distribution is never static. Surge Storm and Surge Riptide training equipment for your home gym are all about the instability of water.