This is your normal, everyone needs and therefore everyone should have it PTFE tube. Will work for 1.75mm filaments and 4mm couplers.
Order these by the meter (e.g. quantity 2 = 2 meters) I can cut these however you wish though, so if you want special cuts of your tube please place a note when checking out.
Note - Transparent PTFE is FEP, and high-temp transparent is PFA (260C)