HTP tig cooler hose

[John T]

Does anyone know where I can find replacement hose for the HTP cooler?

I feel it’s some kind of metric size possibly?
I’ve tried a couple different hoses
3/8
5/16

And it’s either too tight or too loose.

I’d like about 6 feet if I can get it

[Oscar]

5/16" is tight, so 8.5mm would be better if available. But I made 5/16" work.

[filetobeef]

looks to be 8mm ID.5/16 will be slightly smaller but should fit .a negligible 0.06 mm or 0.003 in smaller.
mcmaster and grainger have metric stuff available.