-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 Certification

Standard for Detecting Leakage Rate of Leak Detector

Standard leak can be divided into: built-in, external.