PowerBlock have been the world's best dumbbell since the company started in 1993. PowerBlocks are perfectly balanced and they are the heaviest, most compact and easiest to use quick change dumbbell available on the market. PowerBlock is the only dumbbell system that can expand to meet your strength needs with expandable sets and steel or urethane weight plates available. 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 1 pair, and at a fraction of the price of conventional dumbbells, saving time, space and money.