You can also get the sleeving coated with heat activated adhesive on the inside - but I don't know about from the suppliers you mentioned.Heat shrink tubing! If you don't have an electronics store nearby, Harbor Freight carries a selection as does marine supply stores.
You can also get complex shapes "trouser" sleeves with a large diameter at one end and 2 or 3 smaller sleeves emerging at the other end - handy for sealing the end of the outer covering on cables with 2 or 3 insulated conductors.