Interchangeable Lenses Design：4 interchangeable lenses with 1.5X, 2.5X, 3.5X, 5X magnification. The lenses are made of acrylic resin, the surface hardness of the lenses reaches 5H grade, which is more wear-resistant and durable. Adjustable Brightness Levels: There are two brightness levels which provide excellent light for illuminating detailed surfaces. Two levels of brightness is available by pressing the switch on the eyeglasses bracket. Efficient Rechargeable Batteries: It can be charged in 1 hour to fill up the battery. Simply plug the USB cord into the head magnifier and the other end into the slot of a USB power source(such as a USB wall charger, a cell phone charger or a power band, not included) and it automatically charges. Save money and energy while enjoying long lasting bright light. You will never need to buy batteries again! COMFORTABLE AND EASY TO USE: With ergonomics eyeglasses bracket, it is comfortable to wear ,better fixed magnifying glass in front of eyes. The headband can effectively prevent falling, thus it is easier to work for a long time. VERSATILE: See your work pieces or text magnified up to 500% original size with high clarity. Perfect Hands Free Magnifying Glass for reading, painting, watch repair, arts and crafts.