... calcium, magnesium, potassium, sodium, lithium seven impurity elements of the total content of not greater than 100 x ppm.( two ) the ... 2mm-360mm2. thickness of wall:0.5mm-12mm3. type:transparent,translucent,milky-white,red,u-shape,twin tube, special shape, etc.4. ... equipment, sterilizing device7. technical datasilicon dioxide>99.95%transmittance of visible light>90%,OH content less than 50ppm,20ppm, ...