... 3) high temperature resistance 4) clear Glass lens for LED flashlight GT-D28-5-1)1)material: optical glass(borosilicate),K9 ... : plano-convex5) shape: aspheric6) main featurea: clear and transparent, no mould markd,no inside bubble and dirtsb: can match up all kinds ... of different high power led ,uniform facula,no collapsar,shadow and dark c:adopt high precisy aspheric design ...