... concentrator glass lens(GT-D22-10-1)1)material: optical glass(borosilicate),K9,BK7,B2702) light transmittance: 95%( ... dark c: adopt high precisy aspheric design and superior optical glass, strictly perform ROHS environmental standard6) application range: ... ,infrared light,pool light, stage light, projector light,optical instrument,astronomical instrument. solar concentrator glass lens(GT-D22-10-1)