Hi guys. Can someone identify the circled piece please? or who makes them. thanks! trying to replace all the plastic reservoirs in the engine bay

 

Thats a coolant expansion tank. A lot of manufactures make replacements for the factory plastic one. I think the one in the picture is the forge motorsport one.

Some double as a catch can too like the Driven Fab v3.

 

I second this post.

Driven Fab's V3 is one of the most widely used one out there and they also have the second fluid container shown in that picture just above the one you have highlighted...

 

thanks guys! I picked up the Driven Fab's V3.

no more passing smog for me