Shower valve HELP

I really need some input to what brand of shower valve I have. I'm unable to get pics of it on here right now but, i cant find any brand name on it. Just a manfact. date. On the outer plate (on shower wall) it has UPC inside a little shield, and Csa also stamped into the metal. Dont know if that helps. I do believe my builder used the cheapest thing he could find. It is 6 yrs old, and i am surprised it is leaking. I am getting a constant drip out of my down spout, and it stops and leaks out to shower head if i pull the diverter lever. I think its the valve inside. I took it all apart, took the valve to Home depot, and Lowes, and True value hard-wear, no help there. I'll give a quick description,
It is made of a clear yellow plastic on base where you can see the ceramic parts inside, the gasket attached is blue, the top is a blue plastic and the brass stem has a green plastic collar. I will greatly appreciate any help. Thanks in advance.
Mark

I have no idea what it may be, but I'd bet that it is a el cheapo no-name from a Box Store that the builder installed. This would be a good time to install a new Delta with anti-scald and a nice trim.

Mark, it doesn't sound like anything I have seen. A picture would help. It sounds like all you need a new cartridge/washer. I am surprised that you couldn't match it up at the big box store. You might have to try a wholesaler to see if they can better match it up for you, otherwise take it as a sign and have the valve replaced with something better...plumbing is one aspect in your home you don't want to cheap out on!

Thanks

Thanks for the help guys! I did find my shower valve, and it is a chinese PROFLO brand. Had to hit the plumbing supply shops. Big thanks again for the help!
Mark