We get this question a lot. We like to say our Dumbbells are "Built Like Tools... Not Toys" Our Patented Dual Dial Adjustment System is designed with 100% metal moving Gears and shafts that are repairable if damaged by accidents or misuse.  YES, Imagine that! if you can break our dumbbell you can actually fix it and that's not the case in the Adjustable Dumbbell World.  If you have accidental or non-accidental damage to our competitors handles, very rarely is there a solution aside from purchasing replacement handles or a whole new dumbbell set.  We purchase and test practically every major brand's Pro Style Adjustable Dumbbells and compare them to MX Select. It is fascinating to see how much plastic is commonly used in some of the largest brand name products. There are alot of dumbbells that look and feel nice on the outside, but when we look "under the hood" we are amazed by what is actually holding together many of the other 50 lbs to 90 lbs dumbbells.