Impressed!
I have tried other brands, but this beats them all.  They all worked to some degree, but not even close to this.  When I'm working out in the gym or out in the cold with a face mask.  If there is ever an extreme situation, which does make the glasses fog, it only lasts for a few seconds.  It has only occurred a couple of times.  I make sure to clean my glasses with only this cleaning cloth daily, or every other day at least.  I've let a couple of friends & sister try it, and they are now buying their own box.
Rating: 5 stars