I spent a great deal of time designing and reconfiguring the components based on an old 7 gallon air tank I had. I am really happy with this system.
You plug this contraption into the wall and the vacuum pump into it. The hose on the left goes to the bag, the hose on the right goes to the pump. I have the pressure switch set to turn on around 23inches and off around 25inches.
This is my latest project I used it on; a pair of fiberglass insole parts for a set of platform heels I am making from scratch.
The difference in part thickness between vacuum press and ambient air F/G layup is about 50%; the 1st pair I made with three layers of glass were only .025" thick. Making parts with the press (when I can) is very rewarding; you know you have got a clean & even part.