I have been using Slater Labs 1600 4ft canula's in my portable Concentrator and 1600 7 ft. canula's for my home Concentrator. The prongs are not as long and are shaped a little different. They are much easier on my nose. I still have issues with the oxygen making my nose run if anyone has any tips on how to improve that it would help immensely.
I find that I prefer the one's that have the little plastic tab between the nostrils as these tend to prevent it from rotating out of my nose, especially when I fall asleep.
I usually wait until the nose prongs start to get stiff then replace. They have a real soft nasal cannula that doesn't make my nose bleed but I don't know the name of it. Judy
These are great super soft & thin doesn't hurt your ear if you lay on your side