Price Phister Bath/Shower Valve part

I own a townhouse with three bathrooms with a PPf single knob valve, push/pull on/off and turn for temperature, shower and tub, circa 1978. The cartridge is plastic, cylindrical with various slots around the diameter, relatively long, rubber seals. (Sorry, I don't have a picture as the house is 65 miles from me) I am told the cartridge is no longer available and the repair is replace the valves. There must be 450 of these valves in this townhouse complex. I can't believe PPf would abandon thousands of these valves. Does anybody have any info on availability of the cartridge or its replacement, if any? I have looked at the PPf web site and I don't see it. Thanks.
Gary

Sounds like a PP Avante. The valves are no longer made, but parts are readily available . Walk into any hardware store...they will have it.

Thanks very much for identifying it from my foggy description. The Avante cartridge is what I am looking for.

Well, I was wrong. The valve does not seem to be a PPf Avante. I am beginning to wonder if it is even PPf, but a 3rd party knockoff used in 188 two and three bath townhomes. I just went through a 2000 PPf parts catalog and it is not there. The knob and trim plate look like the Avante, but the cartridge is more cylindrical its entire length, with some grooves and o-rings, and is white. I was told that the Avante cartridge has always been black. Several years ago the cartridge I am looking for was available in most hardware stores hanging in the faucet repair parts section. Now I can't find one any where or anyone who even knows what I am talking about. I will see if in the next several days I can find an old cartridge to photograph. Help is appreciated. Thank you.

cartridge

It could be a Moen.