THIS MODEL IS A 2.0 MAGNIFICATION WITH A 10 INCH WORKING DISTANCE - The following represents the working distance for other models: 1.50X (912) has a working distance is 20 inches 1.75X (913) has a working distance is 14 inches 2.25X (915) has a working distance is 8 inches 2.75X (917) has a working distance is 6 inches 3.50X (910) has a working distance is 4 inches last digit of model # = dioptor ex: 917=7 dioptor is curve of lens not power, curve results in power.