PowerBlock U50 Adjustable Dumbbells - 2-22.5kgs The U90 Stage I Dumbbells have a weight range of 2 - 22.5 kgs per hand and will replace 16 pairs of dumbbells or 374 kgs of free weights. Increments achieved with the U90 Set are; 1, 3, 5, 7, 8, 9, 11, 12, 14, 16, 17, 18, 20, 22 and 22.5 kgs per hand. The U90 Stage I Set is expandable later to 41 kgs per hand with the U90 Stage II add on Kit, and again to 57 kgs per hand with the U90 Stage III add on Kit. Contains Adder Weights. Ships in 2 boxes. Warranty: Urethane PowerBlocks come with a Lifetime Home warrantee. The Urethane Series also comes with a 3 Year Light Commercial use warranty (supervised environment).