The M18 is a long-distance, heavier duty backpack. Great for commuters, hikers, and ultra-long distance activities! This backpack is 18L meaning you have room for everything you need! Equipped with a rechargable LED light on the back for increased visibility. It also comes with a high-viz orange raincover! The M18 is designed to carry most of the weight on your hips giving your upper body more natural, free movement while reducing bounce effects. Also, designed with chest comfort in mind by disposing of the perpendicular cross straps and providing comfortable diagonal, stretchable, adjustable chest straps with a quick-release Velcro latching design. The M18 does not come with a hydration system meaning you can customize to your own needs.