Victorian Horn-Cased Set Of Magnifying Glasses. This is a silver Jeweler's Loupe with 3 swing-out lenses: 1) 2 cm in diameter, magnification X4. 2) 3 cm in diameter, magnification X3. 3) 3.5 cm in diameter, magnification X2.5. Using the combination of 1+2 will provide a magnification of X8 and using all 3 lenses will provide a magnification of X20.