... 3) high temperature resistance 4)clear solar concentrator glass lens(GT-D22-10-1)1)material: optical glass(borosilicate),K9,BK7 ... 97%) 3) Size: 4) shape: aspheric5) main featurea: clear and transparent, no mould markd,no inside bubble and dirtsb: can match ... , projector light,optical instrument,astronomical instrument. solar concentrator glass lens(GT-D22-10-1)