This model is available in three different colors which are designed to blend into your vehicle: Black (3520B), Gray (3520G) and Woodgrain (3520W) with the base model number being 3520.
The point of this particular steering wheel attachment is to allow drivers using a set of hand controls (like MPD manufactures) the ability to confidently and safely turn the steering wheel using just one hand while the other is occupied by engaging the acceleration/brakes.
It’s worth pointing out that in most countries steering knobs such as these are actually banned because they allow the wheel to be turned too sharply and were prone to cause accidents in the past.
Just remember that for countries such as the UK and USA there’s nothing stopping someone using them as a driving aid so long as they’re disabled and hence have a valid reason for using it.
If you want a device to help you steer but aren’t interested in this knob then it’s worth looking into the tri-pin steering control which I personally believe is the best on offer in terms of supporting the hand both while resting and turning.
Remember that this can be detached right away without requiring tools or professional help and is suitable to use with other driving devices which also allow rapid conversation of the vehicle to regular able bodied driving as opposed to being used be handicapped people.
There are lots of different steering wheel steering aids which Mobility Products and Design manufacturers and these are all worth looking into.
It’s also worth pointing out that MPS Monarch has a similar spinner knob which is useful if your local disabled car dealerships do not stock MPD products.
I’ll be honest when I say that both products are very similar, and the reality is that most knobs are almost exactly the same with the real difference being in price.
You’ll find that like MPD most of them have quick release functions, although if they don’t it doesn’t dramatically affect able bodied use so it’s hardly a big issue.