Wrap it and strap it. Similar to the multispinner but symmetric.
Get your wrist locked and loaded for some cupping training. Use the optional hand strap to secure your hand to the barrel to isolate the wrist, or go without it and use more grip strength.
The bigger the barrel, the more finger activation. More thumb activation too if you're going strapless.
Barrel length is 9" to allow ample room for the hand and strap wrapping.
Other shapes and sizes can be requested.