Your bandolier is a weapons organizer, if you carry more than 1 weapon, for different skills, etc (1hb, 1hs, piercing, 2hb, 2hs). By pressing your "B" key, your bandolier opens. You can then set up hotkeys for different combinations of weapons. Initially, you get 4 slots. For my ranger, I have set up 2hand slashing, 2hand blunt, 1hand slashing/piercing, and 1hand blunt/piercing. With this AA skill, you can add a total of 2 more slots to your bandolier. As I mentioned above, with another slot available, I can make a 1hand slash/blunt combo. It is usually situational, for which combination or weapon I want to use, but I use it mostly to switch out weapons when I want to practice a different skill.