SE Jeweler's Loupe- Double Power 10X 20 X New 20X 10X Chrome Plated Eye Loupe. This is a new dual power loupe made of optical glass with a 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. It is 10X power on one end and 20X power on the other. The 20X has a 12 mm lens and the 10X has a 18 mm lens. The 10X lens has a focal distance of 1" (25 mm) and the 20X lens has a focal distance of 1/2" (13 mm) These are second over runs from china. This could be 17 or 18 mm or double or triple lens and it may be misprinted. This is a great bargain at an inexpensive price. Please no e-mails with request because we can make no guarantees.