Having a solid core ("hara") has been one of the cornerstones of the Japanese martial arts. Through Pilates, the idea was transmitted all over the world and the quest for the best tool to build it began. If you are among those still looking, the SixPad Water Weight Training Board from MTG might very well mean the end of your search: the idea behind it might be simple, but this is a superb exercise instrument that will work your abdominal and lower back muscles in the most effective way.
Basically a tube with handles that only needs filling with water (start from 3 liters and add as you become stronger) and it's then ready for use. Either as a barbell for standard exercises like lifts and squats or as a kettlebell that you move around trying to control the fluctuations in weight as the water moves inside it, the SixPad Water Weight will give your core the perfect workout. Get it and get in shape.
The SixPad Water Weight Training Board features: