The workhorse of Gregory's backpacking ventilated line, this durable yet lightweight pack carries like a dream. Thru-hikes, lightweight three-day weekends, or trips to the crag are just a few places you'll enjoy wearing this classic. The z55 features the JetStream LTS suspension, auto-fit harness system, dual hydration ports and sleeve, expandable front bucket pocket, side and bottom compression, quick access waistbelt pockets, dual axe/tool attatchment points, water-resistant welded zippers and 210d HT double box ripstop and broken twill nylon fabrics. Sizes: M (3350 cu. in./ 3 lbs. 5 oz./ 18" - 20"L torso), L (3660 cu. in./ 3 lbs. 8 oz./ 20" - 22"L torso).