KEEP YOUR LIQUIDS COOL FOR OVER 4 HOURS!!!! Excellent condition!!!! FEATURES OF THE HYDRO FLASK HYDRATION 20L PACK Easy access front pocket for keys and otheressentials Perimeter zipper for inside access Cell phone pocket HydraPak® Blaster™ Bite Valve Magnetic Hose Clip Waterproof fabric with taped seams and sealedzippers help keep moisture out Puncture, tear and abrasion resistant, yetlightweight Harness system has an articulated back panel that lets air flow between you and your packto avoid trapping body heat or transferring warmth to the water inside FDA food grade, BPA-free reservoir Advanced construction is designed to maintaincold water temperature and cut off paths for heattransfer HydraPak® IsoBound™ 3 L insulated sweat-proofreservoir helps to protect water temperature forhours Insulating neoprene internal sleeve with reflectivematerial protects reservoir from heat transfer Designed to keep water cold for over 4hours