The DeRosa summary explains the white LS sleeves pretty well. I have two additions:

I don't see a need to replace these at two year intervals. Ours have been in operation at least 8 years and sofar show no signs of wear or loosing tension.

I can confirm installation in 5 seconds, but that goes both ways. These sleeves easily get pulled off when dismantling the wings. We once had to return to an outlanding field to find a lost sleeve. I recommend keeping a spare.