Made of 600D and rip stop with water resistant coating. Front zippered pocket has webbing gear attachments and two side zipper pockets with hooded zippers to protect from all elements. Hidden zippered pocket contains a high-viz rain cover. Bungee cords on top and front will hold extra gear. Main compartment with cinch top closure, has a mesh zippered pocket and elasticized pocket. Heavy load backpack uses Cool Sweep system with air mesh shoulder straps. Adjustable unisex sternum strap and padded waist strap. Emergency whistle built into the strap. This pack is (H20) hydration compatible. Upgrade with the HF00 2L bladder.