Help identifying what this is and how to remove it

[Attackspike]

Hello - I'm trying to fix my leaky shower faucet, and it's made by Moen, though I am not able to identify the model name. When I removed the shower handle and the outer tube, this was inside. Because it's made of plastic, I worry about trying to pull or twist it and cause damage. Does anyone know what this is and how to remove it? thanks a bunch.

 

[TomFOhio]

Can you take a picture showing the inside of the cartridge.