I use the same one that Russ does, as well...One thing to point out is that Russ stated that his is 1.75 times magnifier...GrayBeard stated a 3 times magnifier...Be careful with these numbers...Some sources refer to the "times" when referencing the degree of magnification, while others use the diopter to reference magnification...Some retailers get these numbers confused...As a result, GrayBeard, and Russ
might actually be using the same lens, but each of them are using a different numbering system to quantify the degree of magnification (Russ is possibly in power, while Graybeard might be in diopter)...These numbers also dictate the focal length that is needed; how close the lens has to be to the work piece.
I ran across a chart on the following website that explains all of this, while researching to buy mine (although I didn't buy this brand)...Note that the original size of the object needs to be added to the number in the power column, because the chart is only stating how much bigger the object appears than the original size (thus, Russ' 1.75 times):
http://www.dazor.com/lighted-magnifier.html