First find your hose
As far a I know the manufacturer ceased production, because the customer whose product that used the hose discontinued its use and our 'small' requirements were sitting on the shirt tails of his demand.
I believe the production equipment was also ancient bulky and is no more.
I belive some was around a year or so back but the internal bore was not concentric to the outer whether that came from the original source or someone trying an alternative method of production I have no idea
Making it is a bit more complicated than turning lengths of rubber tube on a lathe with a knurling tool
(joke!) but if anyone can think up a way of doing it in his shed he might sell a few hundred feet....