... ,no pollution, no harmful radiation. - Has the function of infrared Gold coated infrared quartz Sizes:- Outer diameter:1.5-160mm- Wall thickness ... Length:20-300mmFeatures:- Its low brightness, high thermal efficiency, the heating time to the human eye can not stimulate. And at ... food ,medicine , paper drying , printing ,Textile , infrared physical therapy, etc. Gold coated infrared quartz heater tube