... efficiency: 95% 5. Material: BK7 glass Name: Led lens ,glass lens,street lamp lens,optical lensDiameter&Size: 5mm to 120mmMaterial: BK7,Borosilicate Glass ... ,PMMALight Efficiency: >97% (un-coated)Lens type: aspheric lens,spherical lens,special lens for street lamp,underwater lamp and industrial lamp ... .For more,please send us inquiry to know it better high power led lens