These are leather pocket slips for folding knives.
They are designed to cover a knife when left loose in your pocket, both to stop the knife from scratching other items such as a phone and also to stop the knife itself from being scratched by pocket change or other items.
There are a lot of models of Alox knives from Victorinox, however many are the same size with different toolsets. For this reason I make a few sizes of pouch and each pouch will fit multiple models of knife.
Please click below to see some common sizes of knife which will fit each size (you can check other models at SAK Wiki):