Multiple Lens More Magnifications - Exclusively designed with 2 lens slots and 1 fixed front round lens(8X), the two back lens slots can be loaded with single one or two lenses at a time from the five(1X,1.5X,2X,2.5X,3.5X). After combination, 31 magnifications can be achieved. Humanized Adjustment- Foldable Lens Allows Free Combination - All lens on the headlamp can be folded when not needed, therefore you can use any single lens or any free combination from the three(1 fixed lens and 2 replaceable lens on the dual slots). Comfortable to Wear- Soft padded headband with two rotary knobs on the left and right, rotate anticlockwise to release the whole lighting frame from the headband so that you can freely regulate the total lighting frame upwards or downwards to the angle that is needed. Tail knob used to adjust headband size for fit over different head, pull it outwards and rotate left or right to get your head size, then press it to lock. As Headlamp Adjustable Brightness- 3 bright LEDs with 2-level Brightness Adjustment. The angle of light can be adjusted towards left / right/ down, and this part can be disassembled as a portable flashlight. Various Usage- Improve your low vision and release your hands in work at one time. So many magnifications available for different use:reading,painting,observing,modelling,repairing,sewing,soldering, jewelry making and other hobbies/crafts.