I bought this product because I first pumping my waterbed and had to change. When connected to the mattress I noticed that the thread is not quite properly mate with the threading on the filler neck of the mattress. Nevertheless, the aspiration went fairly smoothly, it was only to hear a slight gurgling. I suppose that some air was drawn due to the inaccuracy of fit. However, water came from none, so I give it 4 stars.
