You should understand there are differences between heat shrink tubing materials. One of the differences has to do with shrink temperatures. Some types of tubing have a low shrink temperature, while others have a much higher shrink temperature, like PTFE shrink tubing. You will need to determine what the safe level of temperatures is, for the material you want to use the shrink tubing on, in order to prevent damage.
PTFE Shrink Tubing Inner Diameters Get Smaller as AWG Sizes Increase
PTFE shrink tubing is categorized based on its AWG size. It is important to understand how AWG sizes work in order to get the right sized heat shrink tubing. As AWG sizes increase you might think the inner diameters on the tubing also increased. However, this would be an inaccurate assessment. Rather, as AWG sizes increase, their inner diameters get smaller. For example, AWG size 0 has a minimum expanded inner diameter of 0.470 inches, while AWG size 10 has a minimum expanded inner diameter of 0.191 inches.