Ergonomic design that has won the HiSeoul Design Award! Experience non toxic fabric around your neck!. 100% German made brand new coolant with NO condensation phenomenon! (dry and cool)! TPU fabric with strong sewing made in Korea doesn’t allow tearing or breaking!. Enjoy cool time for 40 minutes up to 2 hours. Cold holding time varies depending on the external environment. No risks of skin necrosis or frostbite through cooling by maintaining an optimal cooling temperature. No battery needed! No charger needed! Freezing starts ANYWHERE below 18°C (64°F). Simply place this neck cooling tube into iced water. No ice around you? No worries! It freezes using any AC! Car AC, Office AC, Home AC, ice box, refrigerator, freezer. Be ready for a hot summer with innovative materials originally developed for NASA to keep you staying cool. This PCM gel freezes faster and lasts longer than water! (Only 10 minutes in iced water and 20 minutes in freezer, or AC air!).