Low pressure lines ID(Inner diametter

I get really cofussed with when it comes to LP lines (FB ,TC,PS and SFR)
I am but interested to know what you guys use.I am only interested in the ID
(inner diameter) of these lines from pump room to the bays.Here in the forum 3/8" and 1/4" are always mentioned but i dont know if they are ID or OD. Thanks

Not to forget,i am using Flojet 57 for TC,FB,and PS. For SFR i am using procon configuration

I did mention in your other thread from some months back that it's OD. Tubing is almost always OD.