That appears to be a Price Pfister tub/shower valve.
Note 1- there are wayyyy more manufacturers/brands than just P.P. and Gerber. And each manufacturer has many (many many) different styles/models/types.
Note 2- it is not just the "stem" that the manufacturer/brand (and style/model/type) applies to; the whole valve assembly is manufacturer/brand-specific.
Note 3- while stems and trim are generally manufacturer/brand-specific and not interchangeable, this particular brand and model is pretty common (at least in the U.S.) and replacement parts are widely available from both the original maker (P.P.) and from others.
Note 4- I highly recommend that you remove the stems and bring them with you when you go to the plumbing shop to get the parts you need.
Answer from Jimmy Fix-it on Stack ExchangeVideos
What are the shipping options for Faucet Stems?
What's the top-selling product within Faucet Stems?
What's the cheapest option available within Faucet Stems?
Having some issues with shower head dripping for a couple months and think I'm going to replace the cartridge which I think is approaching its second decade, am also going to replace the trim kit so matching current brand is irrelevant, but wanted to make sure that these are universal.