CamelBak M.U.L.E. 100 oz Hydration Pack (Envy Green/Graphite) Quick access overflow storage with dual compression straps. 549 cubic inches of cargo Air Director back panel with Air Mesh harness for enhanced ventilation Durable Splash guard protects pack from mud and abrasion. Secure storage for pump, tubes, energy bars. External zip pocket with key clip and organizer for essentials.