Ozone free quartz tube is used for making "Ozone free" UV sterilizing lamp. It is transparent and cut surface is slight purple. Doped with Ti, it can prevent radiation of high-density UV rays but generate no ozone. Spectrum transmission at 185 nm is 0 and no ozone generated. UV transmission at 254 nm is more than 90%. The UV sterilizing lamps made by electric melting quartz tube have much longer life than fused quartz tube. http://www.fudongquartz.com/fused-quartz-tuebs/ozone-free-quartz-tube/