They are the same diameter. They are sunbox "cappy" bottles for the E8.
Bro, trust me, you don't want the link. The bottles are like $9 each. I originally got em because I figured they had a cap that would allow you to fill them in advance and have them ready to hot swap. I shoulda asked before I ordered

. But there is a special kinda feeling that comes with knowing you have a $13 (when you factor in ups shipping from Italy on a set of 11) Italian made bottle in your
mod. It says "you are a genuine baller" but in an invisible
sense
But if you search up sunbox "cappy" bottles it should take ya there. That's all the enabling your gonna get from me.
I will say that I like the way the cap and hose interface works and I am pleased. I just wished they also had a sealed cap so I can have prefilled bottles at the ready or for vacations.
I'll figure out a way to efficiency seal them. - maybe superglue an airsoft BB to the hole on a few of em or something.