Power Blocks are the world’s best Dumbbells. Why? Power Blocks are perfectly balanced. They are the heaviest, most compact & easiest to use quick change dumbbell. Power Block is the only dumbbell system that can expand to meet your strength needs. Start with a 22.5kg set, expand to 41kgs, expand again to 57kgs. Dumbbells are the most versatile & 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, & at a fraction of the price of conventional dumbbells.