Not legal to use on public roads in AL, AZ, CO,FL, KY, ME, MA, MN, MO, NE, NV, NH, NJ, NC, OK, PA, RI, SC, TN, TX, WA, and WI.
Legal in the following states if it can be easily removed (ie, without tools)-- AK, CA, CT, DE, HI, IA, KS, LA, MD, MI, MS, MT, NY, ND, OH, OR, SC, VT, WA, WV, and WY.
Free-for-all in the other 7.
The Zone Tech steering wheel spinner gives you the power and ability to pull off some really tight car moves.
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There’s a reason these are called “suicide knobs”.
The only appropriate use is on old style farm tractors without power steering.
YMMV.
The reason real race car drivers don’t wrap their thumbs inside their steering wheels is because one sharp bump can break a thumb. Ditto for Brody knobs (their original colloquial name), plus add broken wrist, busted elbow, etc, when that door knob whips out of your hand.
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Uh, OK. So now the equivalence class is “things that are inherently dangerous AND things that are only dangerous because they are defective.” Persuasive argument you’re making there. 
Great for riding mower when you got a beer in the other hand.