This is a great entry-level external frame backpack based on Outdoor Products lightweight "Enduroflex" frame.  It's designed to be sturdy yet flexible.  Over the frame is stretched a mesh suspension system that keeps you cool as you forge ahead.  Ultra-padded shoulder straps and hip belt distribute the weight evenly across your back and hips for a comfortable carry.

The Enduroflex frame offers an abundance of adjustment of suspension attachment points both laterally and vertically.  Adjustable attachments include shoulder belts, hip belts, load lifters, stabilizers and back panel.   It is designed to accomodate "Small" to "Large" torso sizes.  Permanent instructions for adjustment are printed on the frame. 

The Firefly includes a large top-loading main compartment, dual side pockets, and large front and bottom pockets with access to the main body.  All together they represent about 3,750 cubic inches of space, a respectable amount for most overnight excursions.  

The Firefly also features an interior hydration-ready pouch that holds a 2-liter bladder (not included) and a pair of side pouches designed for easy water-bottle access (each will accommodate a 0.5-liter water bottle). Lashing tabs are included on the bottom for attachment of tents or sleeping bags.  The Firefly also includes a couple of straps that compress and hold everything together, including a Bungee system on the upper flap and top and mid compression straps.  Theres also an included rain cover for those times the weather is uncooperative.