OTG - Over The Glasses: This model of goggles are designed to allow the user to wear their prescription glasses and the goggles at the same time. Large eyeglass frames sometimes fit less elegantly, but pretty much all glasses are compatible with this goggle. OTG goggles are great even for those without glasses, the larger frame size provides great field of vision.
No Fog(tm) treatment: This lens has been treated to reduce or eliminate the chance of them fogging up from a build up of moisture.
Double Layer Lens: These goggles have a double layer lens, designed to reduce or eliminate the 'fogging' inside the goggles when there are quick changes in temperature. A layer of foam along the edge cushions the lenses for durability and to get a little bit of air and moisture movement.
Helmet compatible: The strap is longer to fit around helmets, as well as hats, without stretching it to the max. Helmet compatible goggles also try to place the adjustment clips off center to not interfere with goggle clips that are on the back of most helmets. The shape of the frame also sits well with most brands of helmets.
Spherical OptiView Double Lens: The most popular (and usually expensive) type of lens is a spherical lens. Spherical lenses give the widest range of vision, as well as minimize glare and optical distortion.
100% UVA/UVB Radiation Protection: Optically engineered to screen out 100% of harmful UVA/UVB rays, so you can ski in the bright sun all day without frying your eyes!
NL-32 Lens: The NL-32 Lens allows 32% of light to be transmitted through the lens. This lens opacity is a good 'all-around' level, which will be good on sunny days and also pretty good on cloudy days. This lens is basically a jack-of-all-trades-master-of-none type of thing.