they fog up pretty good, most of the time i just take them off when hiking or when working. the slider feature isn't what its cracked up to be, it is just an additional piece of plastic that sits between the lenses and covers over the vents. i always had to open the vents as they always manage to work closed. they are pretty small too, probably good for a teenager or those with smaller faces/heads. the strap is a bit cumbersome and really not that helpful. A good bargain vs. "value" priced Oakley's, not for the core rider.