The Chemlight Tactical Light Sticks by Cyalume are premium military grade light sticks designed for military use. Each 6-inch light stick provides 360-degree illumination for 12 hours plus. With a visibility distance of up to a mile (on land), these light sticks are waterproof, non-toxic, non-flammable and floats. To activate simply bend, snap and shake. Each light stick also features a hook and gates top which allows you to hang or attach the glow stick to equipment or clothing. Each glow stick meets the various International defence and NATO specs and has a shelf life of up to 4 years from the date of manufacture.