Bergeon 4422-3.5 is designed to be held in the eye socket to keep your hands free for working. To protect your eyes, the magnification factor of the loupe should only be as high as necessary. With the help of tweezers, you can open the inner screw ring. Then you can remove and clean or change the lens. Housing: Plastic Lens: Mineral glass Linse Ø: 22 mm Colour: Black Magnification: 2,8x Material: Plastic Number: 3,5