In the current climate that the Home Fitness Industry is in, cast iron and rubber dumbbells have been getting increasingly harder to find. One of the alternatives that have had a greater availability in the most recent months have been the PowerBlock adjustable dumbbells. The benefit of the PowerBlocks over traditional dumbbells is that the PowerBlocks are a self-contained adjustable dumbbell that starts at 2.5lb and can potentially go up to 90lbs on their home sets and 175lb on commercial sets. Since the dumbbells are self-contained, they are space saving and are cheaper than buying the equivalent amount of regular dumbbells. The most popular of the models are their expandable versions, either the Sport Exp or Pro Exp. The difference between the two is the Pro Exp has a urethane coating making it a tighter fit so there is less rattling, while the Sport Exp is solid steel. Read about the history of PowerBlock.