Anyone know the name of the U shaped hose that runs from the thermostat housing?

[Vicky27]

I found that there's a leak in one of the coolant hoses. A pressure test was done and it found that the small U shaped hose that runs from the thermostat housing is the source of the leak.
Need to replace but I don't know what to ask for?
Have attached a pic its the hose on the bottom.
Thanks