Help me, I'm mildly confused. New to 4x5, I purchased an 8x10 unicolor PAPER drum and motor base for developing my negatives following a number of recommendations here and elsewhere. In use the drum leaked, an annoyance at best. Searching the web this is apparently a common problem and a number of respondents talked about a plastic ring and underlying gasket which caused the problem. Also there was discussion about a locking arrangement on their drums. However my drum does not have these features. The head does not lock, it only has a locator pin and a press fit onto the drum. There is apparently no gasket, just what looks like a plastic "o" ring I think molded right to the head. Also, the ends are not externally smooth as seen in some photographs but have a crinkly finish. So what do I have here? Is this an older or newer version and where is the seal to prevent leakage? Otherwise it has the separator, internal ridges and works OK.

Richard