Safe Indicator: The Red-Line Indicator Warns User of Any Vacuum Loss. When it shows less than 100% vacuum left, simply pump the plunger until you reach the original vacuum pressure without removing the cup from the glass.
Quality Guarantee: IMT is a professional manufacturer of glass suction cups through the CE, SGS, RoHS, PAHS certification. If you have any questions about the product, please feel free to contact us, Lifetime 100% satisfied quality guarantee.