No offense to anyone, but please add 'I think' or something like that unless you are sure.
BS1623, Standard tubing (extreme, surfer, etc.) has an inner diameter (ID) of 3/8" and an outer diameter of 1/4" (therefore math will tell you through subtraction that the tubing is 1/8" thick, right?)
Max - I've got a feeling this Silcon isn't going to be appropriate for vape tubing.
Why? I am certain many happily use it...
I also agree with whoever said that the vape gives more resistance as tubing gets longer (maybe start with 5/6' and cut it if the draw is too tight for your liking?)
Hope this wasn't too harsh (and, as always, hope this helps
)