... including Zygo interferometers, Perkin-Elmer Lambda 900, Radius tester, and Spectrometer ensure the quality. Our senior engineer can provide ... . Our products are used in telecom, laser, survey and science research. A large high quality standard products are ... Glass, Fused Silica, Silicon, Ge, ZnSe, MgF2Standard SpecificationDig and Scratch: 60-40Center thickness tolerance: 0.03-0.4mmDiameter Tolerance ...