3 Folding Magnifying Glass 10X 20X 30X Powers Loupes 30X Eye 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). The lens has a 21 mm diameter 20X & 10X 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 guarantees10X 20X Dual Loupe. This is a new double lens folding pocket magnifier. Both lenses are 10X and you can combine the two for a total of 20X power. The glass lenses used in this folding pocket magnifier provides durability for a long life. The durable plastic swing-away case not only provides a protective cover for the lenses, but serves as a handle as well. Each 10X lens has a 1" (25 mm) focal distance. When combined for a total of 20X, it has a 1/2" (13 mm) focal distance. Measures approximately 2 3/16" x 1 1/2" x 1" (56 x 38 x 25 mm) closed and 3 15/16" x 1 1/2" x 1" (100 x 38 x 25 mm) open.