All the features of the Overlook 500 Chest Pack plus an additional backpack. Turn the Overlook 500 ZS Chest Pack into something more with an additional back compartment that can replace the standard back pocket with just a few simple strap and buckle adjustments. The additional mini backpack uses the same four point harness system as the traditional panel, and adds a lot of additional carrying hydration capacity to the chest pack. The hydration compatible back compartment adds 550 cubic inches (9 liters) and will hold up to four large fly boxes, or many other items the angler needs to bring on the water. The additional back panel features a D-ring net clip as well as ZeroSweep™ daisy chaining for attaching additional items to the back pack.