Interchangeable Clear Lens: Upgraded headband magnifier provides higher magnification of 1.5x, 2.5x, 3.5x, 5X. The lenses are interchangeable according to the desired magnification. Acrylic optical lenses are made of high quality materials, which are durable, waterproof and scratch resistant. Rechargeable USB interface design: This helmet magnifier has the obvious advantage of being lightweight compared to the heavy 3a battery powered magnifier. You don't have to worry about getting dressed for a long time. Multiple USB power sources: wall charger, phone/laptop charger or charger (not included). You will be amazed by the fast charging and longer lifespan. Adjustable Brightness Levels: LED magnifiers also have two brightness levels. You can easily turn the lights on or off with a switch. Press once, down; Step into the light again. Once again, the light will turn off. In any darkness or gloom, the magnifier will provide sufficient brightness to accurately illuminate the surface of the observed object. Save money and energy while enjoying bright and long-lasting light. Wear Comfortable Straps: They are equipped with elastic straps, which are non-slip and relieve head pressure. Ergonomic frame with soft forehead pad, no manual magnifier, ideal for long hours of eye work. When you move to another place, you don't need to readjust the position, brightness and lens of the light. Nevertheless, you'd better take a rest to soothe your tired eyes. Excellent work on close-up projects: The headband magnifier is an extremely practical accessory for reading, sewing, painting, modeling, welding, repairing, hobbies, crafts, inspection, jewelry and other close-up work. If you have any questions during use, please feel free to contact us.