Cyalume ChemLight Military Grade Chemical Light Sticks, Blue, 6" Long, 8 Hour Duration (Pack of 500) ChemLight military grade blue light stick for providing illumination for up to 8 hours Measures 6" long and provides 360 degrees of illumination Meets military specifications Chemiluminescent substance is non-toxic and plastic body is phthalate free for safety Four-year shelf life from date of manufacture for a maintenance-free alternative to other lighting