I pulled this cartridge and can't seem to locate the brand. The trim ring says Delta, all of the body sprays are Delta, but there are no markings on the valve or the cartridge. I have tried my local Delta dealers and talked to Delta customer service. They all say it's not a Delta. The customer says it was installed about 4 years ago. The supply house where it was purchased is now out of business. Has anyone ever seen anything like this? The 2 disks at the back are ceramic if that helps. Thanks.