BL Universal Non-Slip Steering Wheel Spinner Knob - ABS & High Gloss Chrome Plated Suicide Knob with Metal Ball Bearing for Easy Installation (Black Platinum) - Perfect for Truck, Tractor & Heavy Equipment Drivers

Excellent quality spinner knob is solid and spins freely and easily. The quality is much better than those I saw in several different auto parts stores I visited looking for one. It can slip a little but stays in place about as well as can be expected. Here are some tips from my experience. Mine is installed on a Mazda CX-5 Touring w/Tech option so it is a leather wrapped steering wheel. It is better if the steering wheel is a little soft so the spinner can grip it better. If you have a hard steering wheel then using one of the spacers will be necessary because they are pliable themselves and will be able to grip the wheel some. There are two different thicknesses with the spacers which you can use either one, both or none.There are two pieces to the metal part that hinge together around the steering wheel. When using the spacers that go between the metal part and the steering wheel, you have to be careful to align them so the small "spikes", for lack of a better word, that are on the underside of the metal parts are exposed and not covered up by the spacers so they can grip the steering wheel and keep it from slipping anymore than it has to. The spikes are dull and will not poke holes on your wheel though they might leave indentations temporarily. That will also be on the back side of the wheel where they will not be seen easily anyway. You also have to tighten down the screw quite tightly so the spinner knob will stay firmly in place.Keep in mind if you straighten your arm out suddenly as a reaction to something or were to hit it thrown forward in a collision, it *will* move (collapse forward) which is a good thing when it comes to not poking holes in yourself but a bad thing if you think you will keep control of the vehicle with one hand on the spinner knob after it moves significantly forward. I highly recommend installing the spinner knob on the inside of the steering wheel, not the outside. Install at about the 8 o'clock position if left handed, 4 o'clock position if right handed because most of the time you will want to rest your arm on your leg or the arm rest while driving.I am very fortunate that my condition is temporary for before and after a surgery when I will be left handed for a period of time. I have a doctor's Rx for the device which I keep in the car and is required by my state to have a spinner knob on your steering wheel. Check with your State Patrol office to see what their requirements are. If you go to another state, my understanding is that they will honor whatever your state does that is on your license plates/driver's license.I love the thing. It operates very smoothly and for the most part, stays firmly in place. If it moves a little I just tighten it up again with a Phillips head screwdriver I keep in the glove box. Even when it slips, it is only a little bit. It never comes completely loose, it just moves a bit back and forth. I wonder if I will be able to give it up when my arm heals?! Maybe I will wait until I at least get a warning ticket. ;-)