PowerBlocks are the easiest adjustable dumbbells to expand, so as your strength grows, they can too. If your PowerBlock is an ‘EXP’ model then you’ll be able to increase the weight of your set up to 90lbs. An expandable model starts at 50 pounds and then gives the option to expand with two 20 pound kits. The ‘Stage 2 Kit’ will take a 50 lbs. set up to 70 lbs., while a ‘Stage 3 Kit will take a 70 lbs. set up to 90lbs.