I bought this specifically to change the oil in my John Deere tractor.  The drain plug on the tractor is fiddly and I usually end up getting oil all over the frame and axle when I use the drain plug.  Using this extractor is so much easier!  Pop the dipstick out, put this tube down the dipstick hole, and pump up the extractor about 10-15 times.  I had to pump it up again about 5 minutes later to get the rest of the oil out.  It made changing the oil in my tractor so much easier.