It works alright. I have it on a Pondmaster (Danner) AP-20 at a depth of 2 feet, and maybe 8 feet of hose. It just seems like there should be more air coming out of the ring. I previously had the diffuser that came with it, on 3 different 6 inch air stones and a ton more air came out of it.
Rating: [4 of 5 Stars!]