Features:18-20L: Main compartment, top and front pouch and side mesh pocket, roomy to organize the outdoor supplies.Waterproof Rain Cover: Come with a rain cover for unexpected rainy days during outdoor activities.Serviceable Material: Made of 210D nylon, water repellent and wear resistant.Comfortable: Mesh shoulder strap breathable for snugly carry, and adjustable waist webbing for proper tightness.Portable: Easy to fold and packed in a pouch for convenient carry.Designed for Outdoor Sports: Emergency whistle, reflective stripes and smooth zipper, all these attentive details are allfor outdoor climbing, hiking, camping and traveling.