6 New 20X & 10X Chrome Plated Eye Loupe. This is a new set of 6 dual power loupes made of optical glass with a swing-away, chrome plated case. The shape allows them to rest comfortably in the eye socket. These has become the standard style of loupe used in the watch making industry and is excellent for any application where magnification is needed. They are 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. They could be 17 or 18 mm or double or triple lens and it may be misprinted. A great bargain at an inexpensive price.