I first used a set of power block dumbells back in college in the 1990’s. I fell in love with them right away. We had a complete set of dumbells there but I preferred the feel of the power blocks. Then about fifteen years ago I was building my home gym and was able to buy a set of 90lb power block dumbells. Soon after I got the expansion kit to bring them to 125lbs. My three kids have been using them for the past 5 years and just bought one of my boys his own set of power block dumbells to have at college. I love them and are the best set of adjustable dumbells I have ever used!