I have used the Fog City shields. They do a good job...if you don't already have a fog-free faceshield. Unfortunately, they won't keep my glasses from fogging. The Fog City shield will narrow your field of vision somewhat, all around. It is still adequate, IMO. In time the Fog City shield will craze, and need to be replaced. Rain-X will hasten its demise. Mine all seemed to get bad before my faceshields did. One last thing, most faceshields these days are UV resistant, so the self-darkening feature of the Fog City shield will usually not work much. Definitely worth the money, even if they are not perfect.