Rolling ChimeraA regular rolling handle getting too easy? Just add a 2nd roller into the mix! The double roller approach allows the thumb to work independently from the fingers, but strength from both sides are required to lift this double headed monster! Rollers are 5" in length and are interchangeable to allow for varied training. Try mixing things up with different size rollers going at the same time. Maybe have the thumb on the larger roller, and vice versa.