People who manufacture it and sell it swear by it.

People who don't have it think it's worthless.

Half the people who have it think it's the greatest thing since sliced bread.

Half the people who have it don't really know whether it works or not.

I have some, don't use it all the time, have been winded with it on, not been winded with it on, been winded without having it on, and not been winded without having it on.

Does it work? My conclusion is that I haven't a clue.