The Simms Headwaters Chest Pack is designed with a catch and release modular system which allows you to dock into both Headwaters backpacks. The main zippered compartment stores 2 fly boxes and accessories. This pack also features a compression molded front panel that creates a fold-down workspace. This chest pack has removable hook and loop floatant holder and tippet spool retainer. This bag is perfect for going light, and is a fully featured mid size pack.