3/8ths OD or ID

[e46cruiser]

So my buddy is going air ride next week and asked me a question I didn't know the answer to so I thought I should ask here. Is the 3/8ths air line size the OD ( outer diameter) or the ID (inner diameter) ? I wasn't quite sure how it was measured. Maybe you guys can help out!

[Alex@BagRiders]

OD:

[upSLIDEdown]

Uhhhhhh... lol

[Oh Damn, it's Sam]

All the stuff I have is measured by the OD, and all the PTC fittings I have (a mixture of of Parker and SMC) are measured off the OD as well.

Also, FYI, if you're planning on doing hardlines at all, you want tube rather than pipe - tube is typically measured off the OD, pipe off the ID.

[ebelp]

Lmao Rali!