This is a food grade heavy duty 9.5mm ID 15.5mm OD silicon hose, suitable for boiling wort transfer. Fits 3/8" barbs and pipe sections.
It is the correct size if upgrading the silicon hoses on Grainfather units for the wort return arm and for the wort circuit on your Grainfather chiller.
Priced per meter. If you need less frectional quanties are available.