标准检漏孔

-8量级的标准漏孔（氦气）国家标准计量单位计量并出具检定证书检漏仪漏率的检测标准标准漏孔可分：内置、外置。-8 magnitude standard leak holes (He)National Standard Unit of Measurement and CertificationStandard for Detecting Leakage Rate of Leak DetectorStandard leak can be divided into: built-in, externa