Bend Keeper for VP Racing Gas Can Tubes.  Notice the name says “KEEPER”.  If you try to print this out of PLA and stick it on a 4 year old tube of automotive/gasoline resistant grade plastic tubing, expect it to BREAK.  It will absolutely work on that 4 year old tubing, but you need to soften it first with hot water or direct sunlight, then put the keeper on there and it will keep the shape.  If the tube is newer, it will most likely be fine without softening (still a good idea), particularly if you print it out of something stronger like PETG, ASA, etc