1.PMMA(optical acrylic) materials 2.limpid transparent acrylics lens 3. ... acrylicGroove pitch: 0.5mm Focal length/Magnification: 880mmfeature ad advantages:1.high light transmittance2.limpid transparent3.high light penetrability,more brighter4 ... is suitable for PROJECTOR,PROJECTOR,EPIDIASCOPE and ,also suitable for Solar energy collector system, start a fire under sunlight, hot water heater ...