Review on Lincoln Electric 615 Suction Gun by Justin Cranford

as others have said. If you suck liquid into it, you have to keep it upright. When injecting you should try to keep it level or tilt it down, but as long as you take your time and don't clog it, you shouldn't let any liquid through the seal. The seal is fairly tight and might require some effort if you're making something like gear lube, but I'd prefer a good seal that's a little harder to push through than an easy one that leaks through. Also, the hose that comes with it is pretty rigid and big. So if you want something more flexible, you may need to replace or downsize it. It worked great for what I needed it for. I've done 3 transmission oil changes with it with no problems and have done a few other things with it as well. I am very satisfied considering the price. If you're a pro and plan on using it every day it might not hold up, but for the average person like me who uses it a few times a year it worked great. Changing transmission oil is now much easier/quicker than using a hand pump!