schreef
I'm looking for a good quality magnifier, one i can keep in my pocket
or key chain. My instructor uses a Bausch and Lomb Hastings{triplet}
20x but the lens is too small for me. Is there one with a slightly
bigger lens of the same quality small enough to keep in my pocket? It
will be used for id of weeds, pests,etc. Thanks.

***
Such questions are not easy to answer, as many factors are involved
(personal habits, size of hands, size of pockets in typical garment, etc).
Personally I find a good field of view most important, which means a wide
diameter lens. I have always been happy with a basic (and cheap) 8x lens,
and went through several of these before they went out of production. When I
needed a replacement, last year, I went to my optician who sold eschenbach
hand lenses. After a quick comparison of all the magnifications in stock I
had no hesitation in buying the 8x lens, this offered much more viewing
field than the next higher magnification (I forgot what it cost, although I
do remember it was not cheap). I have a wide diameter 15x lens here
somewhere, but I cannot say I am using it much.

I suggest you go to a shop with a good selection of lenses and make a direct
comparison (it is a good idea to bring an object to look at, with lots of
interesting detail). Then watch for the amount of distortion towards the
edges of the lens.

A quick google turns up http://www.kooters.com/sezlens.html (it is linked to
a webstore) which offers useful comments.

Hope this helps,
PvR