Question for gas fitters

What are these things called ... they go on either end of a buried gas line.

Anodeless sweep for direct bury. Prevents the metal pipe from inter acting with minerals in ground.
They are used with a poly pipe for gas
In my state we run a yellow tracer wire with the pipe attached on either end above ground

It is called a riser pipe. It must be used to transition from an underground gas piping system to an above ground gas piping system. Codes require them. They are steel for better abrasion protection when coming out of the ground to the meter. Under ground you use a poly pipe [MDPE] with a ground tracer wire.

Thanks guys. I'm pretty sure the yellow coiled pipe is copper. That's what was used to run out to my shop. Probably depends on local codes I'm guessing/

The outer casing numbers should tell you something. The risers you have the yellow connectors on the end are for poly pipe. MDPE is most likely on that yellow roll.