The belomo 10x21mm(0.85'') triplet loupe magnifier has a viewing area of 0.65" (17mm), much larger than the bausch & lomb hastings triplet magnifier. The large 21mm (.85") 3 elements lens making up this achromatic triplet gathers lots of light to provide a bright, clear, and color correct view. The 10x power magnification provides the best magnification to depth of field ratio and is the most poplular power for a handheld magnifier. The housing and cover have a matte black finish for gem grading. Belarusian optical and mechanical association (beloma), makers of telescopes, camera lenses, and other optical components manufacuturs these loupes. Highly recommended by the amateur geologist. This is the lens we use all the time. Don't let this price fool you. The belomo loupe is a fantastic buy. These are optical quality lenses, each one inspected and certified just like a camera lens, that stand on their own against the higher priced competition. Belomo loupes are assembled using screws rather than rivets which allows them to be adjusted. Every belomo loupe shipped by amateur geologist is custom treated to prevent the screws from coming loose with usage. Don't be fooled by cheap loupes selling for nearly the same price of more! many don't even tell the manufacturer. Why? because they're cheap imports from china, japan, tawain or elsewhere which typically cost less than a dollar at import. If you don't know the manufacturer how can you know the quality? is each lens tested and does it include the certification just like a camera lens? the belomo does. Triplet means three lenses made of different types of optical glass bonded together and designed that, together, they straighten out the light that comes into the front of the loupe lens so that it's the same when it leaves. Cheap import triplets are just three identical pieces of glass, not bonded, that distort the image. 18 month warranty on all belomo 10x triplet loupe magnifier sold by us merchants.