Rolling Double BarrelSimilar to the Rolling Barrel, but with twice the trouble! Having 2 rollers mean both your fingers and thumb will all have to work hard, and in balance with each other. The weaker side will be the one that slips off first, which could act as great way to help identify weaknesses in your vertical grip. The rollers sit between bearings to allow smooth action and minimal friction. The rollers are interchangeable with other 5" Nemesis rollers and can