<b>G4Free 3 Day Expandable Outdoor Large Backpack:</b><br><br><br> 1.The 3 Day Expandable Outdoor Large Backpack with Molle compatibility that allows customizing the pack for your needs.<br><br>2.Main compartment expands an additional space to accommodate vital assault gear to complete your mission. It expands from 45L to 50L.<br><br>3. Integrated breathable mesh pad in the back, breathable and not muggy. The waterproof nylon fabric, prevent the items inside from being wet.<br><br>4.The smaller pocket on the rear contains an organizer pocket inside.<br><br>5.The back padding can carry a hydration bladder (bladder not included) inside the main compartment and has a hydration port.