The Quick-Lock Dumbbell Add on Kit adds 45 lbs to each dumbbell to bring them up to 120 lbs each. Includes four longer locking screws and four 22.5 lb weight plates.
You can put the big plates on the handles first (recommended) or add them on top of the original plates. Very simple to use and works just like the standard plates and locking screws. The longer locking screws allow dumbbell sizes of 70-120 lbs. The standard Quick-Lock dumbbell stand (sold separately or with the 75 lb set) will hold the full 120 lb dumbbells. Even with this serious amount of weight, the dumbbells are still compact. The dumbbells are just 19" long overall at the full 120 lbs.