Use this jig to make yourself your PTFE tubes instead of buying them, it is a lot cheaper to buy a roll and you can make the length you need, instead of buying expensive set.
Bambu Lab use 2.5mm ID (inner diameter) and 4.0mm OD (outer diameter)
Usage : Insert the PTFE tube into the jig until it reach the end, use a sharp knife and cut into the slot (see pictures)
Here are the sizes for each models (you can find how to replace PTFE tubes in the wiki)
The jigs fit in a filament box for storage ;)
X1 Series / P1S
P1P
AMS
A1 Mini
A1