12 Weight Increments and Adjustable: Experience 12 weight settings in one dumbbell, accommodating exercises from novice to advanced levels. The weight increments include 3, 7,13.5. 17, 20, 24, 27, 29, 31, 36 and 40 lb. Safety-Enhanced Design: This dumbbell features a locking mechanism designed to ensure weight plates stay in place during use. The locking mechanism allows the handle to be rotated when it is inserted and engaged with the dumbbell base while also locking the dumbbell handle into the base. It also prevents the weight plates from dropping off the dumbbell when it is not in the base and prevents partial selection of the weight plates.