NEW STEP BY STEP MAP FOR PVC VALVES

So espresso baggage have these ingenious one particular-way "degassing" valves on them product of membranes that open up if the force builds up within. That is why you could "wake up and smell the coffee" with no in fact opening the bag. When air tries to push in from exterior, it flattens the membrane and seals the bag tight. To date so good, but