The large format extender allows for adding large type weightlifting plates to dumbbells. It spins on and off onto the MagWEG 5 pound disc.  Combined with the MagWEGG one can now easily increase their dumbbell by 10 pounds and up with the plates they already own. 

Composition of dumbbells vary but one can generally safely add 20 pounds to the combination of MagWEGG and the extender to a typical cast iron dumbbell.