Specifications ф40-200mm, the SiO2 content ≥ 99.98%, Al, Ca, Mg, K, Na, Ti, Li, Ni, Cu, B, Cr total content ≤ 45ppm. The product has good heat stability, electric insulation performance, transmission performance, acid-resistant properties, widely used in high-tech field of semiconductor technology, integrated circuit manufacturing, optical fiber communications, laser technology, aerospace technology, national defense, military and optical industries