Unknown brand & unknown part

[5150Jim]

Hello
I'm new to the site but I just bought a house & there is a few things that we might be changing.
First, my wife said the water in the shower isn't hot enough.
I text the previous owner & he said there is a heat restrictor. I'm not sure what that is & I have tried to Google it with not much luck. All I can find is shower head restrictor or flow restrictor.
I think it is something to keep you from turning the handle past a set spot.
If that is correct, I did take some pictures of the handle assembly.
I guess my question is, can I take out this black plastic part (because it is to big for the hole & I will have to cut it up to remove it) or will that make a problem for me?

 

[Twowaxhack]

I believe there’s a hot water limiter under the dome cap that you haven’t removed yet.

 

[5150Jim]

I found that the center has a hex shape but I don't have a tool that will go in there

 

[5150Jim]

Nobody in my town has a tool to fit in around the spline so I got in with my channel locks & got it off & was able to pull the restrictor. TNX for the info

 

[Twowaxhack]

The part you’re holding in your hand is two pieces.

The dome piece is separate.

You had to turn the water off to remove the entire thing. You shouldn’t have to do that just to adjust the hot water limiter.