The WEGG Ultimate includes WEGG1, WEGG2, WEGG 3 and WEGG4.  It adds weight in increments of 1.25 pound up to 22.5 pounds to any dumbell.  An 10 pound weight is transformed into a 22.5 dumbbell!

 

Combining all four WEGGs does require testing of each dumbell intended to be used.  Great care has been done to make sure that this combination is possible.  However, if the dumbbell that you own does not have adequate magnetic material then one may need to use a different dumbbell.