I have several DuBro final filters, the ones made of aluminum, about 1" long. They are closed at both ends, but one end can't be opened and the other end has what looks like an "O" ring fitting. I can't remember which end is supposed to go toward the engine, and was wondering if someone out there would know. It may not make any difference, but I seem to recall the instructions, which I threw away, gave a certain direction for installing them. Thanks.
Glen Wearden