Air Pressure Switch, brilliant for a simple solution to sending air to an air bag and then exhausting the air out. This is simply plumbed up with an air line coming from your source of air (tank etc) then another air line goes from the paddle switch to your air bag (or other pneumatic item). Push the switch up and it sends the air through, let go of the switch and it keeps the air in the air bag and blocks off the delivery. Push the switch down and it simply exhausts the air out of the air bag through the back of the switch. The barbs on the back are for standard 1/4 inch airline. The face is 25 mm x 45 mm, the hole for it to sit in will need to be 21 mm x 41 mm.