Review on HiLetgo 328PCS Heat Shrink Tubing: Versatile Insulation Solutions for Various Applications by Sean Garrison

For $7 you get a nice case with multiple sizes for different wire sizes. It's pretty standard, but the larger sizes come flat-packed so you just have to roll them between your fingers to round them back up. I use a heat gun so can't tell if a hair dryer or the like will reduce it, but performance was as expected and it responds perfectly to a small amount of heat from a soldering iron if you need it one-handed. fix as a last resort.