: borosilicate glass. Size: diameter about 30/44/54/66mm/1.18/1.73/2.60in. Working temperature&Luminous angle:Working temperature: -50-220°;Luminous angle: 5-60 degrees. Light transmittance: more than 97% . Light refractive index: 1.47. the actual light angle can be obtained by adjusting the distance between the lens and the LED. Application: Suitable for LED spotlights, car lights, flashlights, and projection lamps. It enjoys uniform spot without black holes. shadow, dark area.