What material node is this?

Hello,

I´m trying to recreate this node function by Robert Berg, I just can´t figure out what kind of nodes those are which I´ve marked in the picture.

Sorry, if this is a silly noob question. I´ve been looking through the starter content materials, the automotive materials and the particle effects demo materials to find something similar so I can figure it out, but without success. I also don´t know what exactly to search for, except keywords like “material node with preview input and 1 output”, “scalar node” and things like that, all of which didn´t give me an answer. Would be nice if someone could help, maybe give me a short explanation aswell what that node does. Thanks in advance!

I just figured it out, it´s a “Function input” node.