Size: 15 x 21 x 8 13'',Main area expands from 5" to 10" to fit more gear 3 Day Expandable Outdoor Large Backpack with Molle compatibility that allows customizing the pack for your needs. Main compartment expands an additional 5 to accommodate extra vital tactical gear to complete your mission. It expands from 39L to 64L. Side parachute buckles allow for tightening to provide a compact, easy to transport pack. The smaller pocket on the rear contains an organizer pocket inside. The back padding can carry a hydration bladder (bladder not included) inside the main compartment and has a hydration port. Durable & Water-resistant Tactical BackpackTactical bag features ultra strong shell fabric and construction are made of 600D Nylon for long-lasting performance. The shell is tough and water-resistant and stitched with reinforced nylon threads. Expandable Tactical backpack size21 "; x 15" x 9" WHEN FULLY EXTENDED; Capacity: 39~64 Liters.The collapsible and expandable design lets you adjust the packs size to fit your gear. Military Backpack with Molle SystemMolle backpack Put a 44 patch panels at the front and back to stick your name patches and morale patches,Heavyweight MOLLE loops and webbing for attaching additional tactical pouches and gear for 3 day assault pack backpack combat molle backpack. Multiple Compartments Heavy Duty Backpack:Military backpack has 3 main multi-compartment and dual zippered closure pockets including interior zip pocket and mesh pocket for more storage options.The main area expands from 5" to 10" to fit more gear. Each compartment has mesh or zippered pockets to store gear.This heavy-duty backpack has a laptop compartment. Backpack for TravelMilitary backpack has hydration compatible that works great for a hydration bladder(hydration bladder is not included) as hydration backpack. It can be used as 3 day assault pack, gym backpack, bug out bag backpack, range bag, survival backpack, army backpack, molle backpack,men backpack, hunting backpack,outdoor camping backpack, travel backpack or day pack for daily Use.