leaks that I would have never found with the regular boost leak tester. It has adapters to fit different holes and a ton of caps to plug off just about any size hole. This finds the smallest of leaks. Found the smallest pinhole you could imagine on my brand new intercoolers. Leaks that size aren't enough to matter but it finds them. I got a good deal on it that I couldnt pass up so I bought 3 of them. Plan to sell two one day. Lol