The lenses are made of acrylic resin, the surface hardness of the lenses reaches 5H grade, which is more wear-resistant and durable. 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. 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.