Reservoir Vacuum Hose Diameter

[Stephank]

As above ,

Does anyone know the diameter of the vacuum hose that connects the radiator with the reservoir bottle ?

I found this website below, as i want to buy one to replace mine, but i'm not sure about the size. Is it 3mm ?
Any help would be appreciated.

Also is this website ok to order? Thanks !

Samco Vacuum Tube from Merlin Motorsport

 

[Stephank]

Anyone?