My faucet is pictured below. There is no manufacturer name anywhere on it. I need to replace its cartridge as the faucet spout is leaking. Below this picture are pictures once the handle is removed, showing the innards. Here is the internals. At this point, there are two nut shaped fixtures (outer brass and inner nylon). I'm not sure which one to loosen. I tried the outer brass piece without much luck. Without knowing if this is the correct part to loosen, I didn't proceed. I'm not sure if it is threaded into the base or not, let alone whether it needs removing. As for the inner nylon piece, there is very little surface area to contact if that needs removing. The outer part is high enough that just a millimeter or two of the nylon nut is exposed. Any suggestions would be GREATLY appreciated! Thanks.