Zpacks Multi-PackZpacks Multi Pack is a 3. 5L water resistant four in one pack that can be used in 4 different ways: as a brain, chest pack, belt pack or satchel. You can basically transform this into whatever you need most of the time. It is very convenient to use and can save you a lot of time on the trail. Configurations: Clip it to the top of your pack as a lid brain. Hang it from your shoulder straps as a chest pack for a large camera, or for carrying water to