The unit that Joe put up the link to is the one I'm talking about. It is small in diameter, but has a fairly large volume in the chamber that you put towards the tank. All fuel filters have a right and a wrong way to flow. I don't fly as much as I used to, but when I was flying my Shark 45s in both classic and PAMPA events, I didn't have to do any extra ordinary cleaning, just regular maintenance when cleaning "under the hood" after several flying sessions, maybe two or three times a year. The Shark 45 has a pretty narrow cowling, and a typical filter can be used but makes plumbing more difficult. These worked very well for me. I just use them on cowled engines, and use the typical filters on profiles. I like the smaller unit that Great Planes has available.
Sullivan Crap Traps used to be susceptible to air leaks and I experienced that a time or two. I haven't used them in a while, but for the price, I like being able to take mine apart. Back flushing doesn't get some stuff out.
Thanks a lot for the deed back,
Dan McEntee