When I first started playing pipes the air hose connector that came with the set was some sort of hard rubber not unlike radiator hose for an automobile. It was sturdy and would never kink. However, it was inflexible and later when I started to play regulator chords it did not want to cooperate with some of the movements involved. I then replaced the hard rubber with a softer natural latex hose. This is nice and flexible and has a lot of grip to whatever coupling you put in it to attach it either to the bag or bellows. However, it will kink or become constricted by the mainstock under certain conditions.
It occurred to me last week that this can be overcome by inserting a small metal compression spring into the hose (you can find these at a hardware store). This has proven to be the best of both worlds (the porridge is “just right”): the resulting combination will not kink, but it is extremely flexible. Just be sure to dull the part of the spring that you cut prior to inserting it into the hose.