I find this product to be a fairly useless piece of equipment. Sure it makes the wiimote easier to handle as a wiiwheel, it doesn't really aid your driving.

The wiimote fits perfectly into the slot, and won't fall out unless you want it too. There is a button built into the back of the wii wheel which works as the B button.

If you do decide to get a wii wheel, for Mario Kart Wii or F1 2010 or any other driving game on the wii that supports it, i definitely recommend that you get an official wii wheel, there are tonens of unofficial ones that are available for about £3-£5, but its worth the extra couple of quid for the better build quality. Unofficial ones don't feel nice, they have a rough texture and don't fit around your hands as well. The F1 wheel that comes with the F1 game was made in the shape of an F1 steering wheel (square) but it doesn't fit around your hands very well. Personally i would stay away from these wheels, i don't find them useful, and there are too many of them out there which don't do the job well. But as i said, get an official one if you do decide to get one.