I have some tylene hoses semi-permanent in my garden to ease irrigation. To winter-proof them (ie prevent frost damage), the hoses and pipes need to be drained, but the lowest point is below the house. With this thing, I can use compressed air to empty all tubes, hoses, connectors, valves in one go. It fits 13mm or 1/2" tubing on one end (to fit to Gardena coupling, for example) and a car valve / tyre pump on the other end. Put the tube/hose in a cup of hot water first, to make it more flexible. Tested to 3 bar.