SE 4pcs Jewelers Eye Loupe 30x Loupe + 3-10X Loupe 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)