Since vacuum-pumps were invented, consumers have been saying, "Show me the vacuum". Because you can never tell if you've pumped enough vacuum to preserve the wine and days later, when you re-open the wine, you can never tell if the vacuum has held.
Now with the V-Gauge Wine Preserver, you simply pump until the needle reaches the "red zone" on the gauge. Then you know you've achieved the necessary vacuum. And later, that needle in the "red zone" tells you your wine has been preserved. A patented Metrokane innovation, the V-Gauge is packaged with a stainless steel vacuum pump.