1) optical glass (borosilicate) material 2) above 94% light transmittance 3) high temperature resistance 4 )clear Material: optical glass (Borosilicate,K9 and so on) Up to 96% transmittance packing and weight : 1 piece /carton box Processing: by design, molding, grinding, polishing, inspection, testing and so onInside quality: clear and transparent, no mould marks, no inside bubble and dirts We ...