This lamp emits beneficial UVB up to 90 cm from the surface of the bulb. Glass and plastic filter out UVB; there should be no glass or plastic between the lamp and your reptile. Fine mesh blocks up to 50% of light and UVB.
This should be taken into consideration when determining lamp distance. The T5 HO ReptiSun 10.0 is designed for most desert reptiles housed in terrariums that are 45 to 90 cm tall. Always have lamp at least 15 cm away from your animal.