Need help removing stem from shower handle

[Mr. Britton]

I don't know if this stem pulls out or turns out. I am not familiar with the type.

Here are the details and some pics"
I have a shower mixer that is 15-20 years old I don't know the brand (maybe Kingstone brass). I have a few pics if that will help. It is a two handle mixer that has a long brass housing that screws over the handle stem. When this brass housing is removed I can look into the hole to see a red cartridge? The red might be something else I don't know all the correct terminology to correctly talk about my problem so forgive me if I use the wrong term.

The leak happened when I hit the valve on accident in the shower going past the off position by a few degrees and that caused the leak. It only leaks when the hot or cold is on and luckily the long brass housing makes the leak come out the handle through the brass housing cover rather than leaking inside the wall.

 

[Geofd]

There are 2flat sides on that peice of d
Brass,that would tell me that it threads off

 

[TomFOhio]

Shower faucet wrenches will take that stem out.