10X 20X & 30X Jewelers Gemstone Combo Eye Loupes Tools This is a new doublet lens loupe made of optical glass with a round swing-away chrome plated case The shape allows it to rest comfortably in the eye socket This has become the standard style of loupe used in the watch making industry and is excellent for any application where magnification is needed In terms of performance, it is second to none It is 30X power and has a focal distance of 1/2" (13 mm)