VACUUM TEST GAUGE for Cans and Jars used to measure internal negative pressure value of the can. Its working principle is the use of tool steel material needle pierced the cover , at the same time use the soft silicone gasket to ensure no leakage , steel needle connect with the vacuum gauge to get a tank vacuum values. Due to the inner diameter of the needle path only 0.6 mm , reduce the error produced by the connect channels, yield the gauge readings closer to the real value of the tank. The product meet the national standard: GB7103-86 Technical Datas Specifications: Model: CVG -100 Measuring Range: -0.1-0Mpa Resolution: 0.002Mpa