Alfa Aid pointed out that mine is on the way out as well, and that they are getting rare.

Judging by eye I think that is just small enough for the build area of my 3D printer and a quick Google says that TPU is resistant to oil which sounds breather hose friendly. A project for the winter perhaps to see if I can print a replacement, though the only flexible filament I have is some Ninjaflex which might be too wobbly so it might need semi-flex.