Beileshi Head Magnifier LED Illuminated Multi-power Helmet Magnifying 1.5x 3x 8.5x 10x Magnifying Tools for Watch Repair, Arts & Crafts or As General Reading Aid This product installs 3 Lenses multiplying power of lens:1.5x 3x 8.5x 10x Providing light source for the glasses if the most suitable for operation or intersting handcraft Circumference of the head strap adjusts with a turn dial located on the back Material of lens:Acrylic (Processed by crack-proof rigid coating ); With detachable light source box ,need two "AAA" batteries (not included). Materials: ABS resin .PP resin; All the lenses of this glasses series are interchangeable.