Other useful features include a light loop, ideal if you're commuting year-round, a raincover to provide total waterproof protection from sudden downpours, secure TipGripper walking pole attachment points, a safety whistle on the chest strap and some reflective graphics next to the logo. Made from robust ripstop nylon with a HydroShield weatherproof coating, the AirZone Active 18 is design to withstand the rigours of trail activity and the sternum strap with whistle is an excellent addition for emergencies. A modern clean design enables the Active 18 to be as functional in the city as on the trail. A large zippered clamshell opening provides easy access to the main compartment. Allowing you to access waterproofs and other items with ease.