PowerBlock

PowerBlocks are perfectly balanced. They are the heaviest, most compact and easiest to use quick-change dumbbell. PowerBlock is the only dumbbell system that can expand to meet your strength needs. Start with a 50 lb set, expand to 90 lbs, expand again to 130 lbs. Dumbbells are the most versatile and effective exercise tool ever developed for strength training. Now you can have rapid access to a whole rack of dumbbells at home in the space of just one pair, and at a fraction of the price of conventional dumbbells