Neck cooler that maintains 28°C using NASA technology. - Brand: monochro - Color: Black - Size: L - Features: P.C.M. material using NASA technology - Temperature maintenance: Maintains 28°C Although it is new and unused, it has been stored at home, so please understand and purchase. ✅【Freezes naturally below 28°C!】 This neck cooler for the neck, made of "PCM material," is the ultimate eco-friendly item that can be used repeatedly both outdoors and indoors. No charging is required. It prevents overheating and is the perfect item for preventing heatstroke. ✅【Passed both antibacterial and compression tests!】 It has cleared a 99.9% antibacterial test and a liquid leakage test, so you don't have to worry about unnecessary issues. As a Japanese manufacturer, we will provide full support if there are any problems with the product. ✅【Can be used for a wide range of purposes】 It can be used for outdoor sports such as soccer, baseball, golf, fishing, cycling, and hiking, as well as indoor sports such as basketball. It can be used in various situations, such as driving during the day, gardening, studying, and working indoors. Always stay cool and comfortable! Please use it to prevent heatstroke. ✅【Smart design】 We want both men and women to use it, so we have prepared a smart design that doesn't look out of place when used indoors or outdoors. ✅【Specs and Usage】 【M】Inner diameter 9.5cm, width 2.2cm, weight 110g (±5) 【L】Inner diameter 11.5cm, width 2.2cm, weight 130g (±5) ★How to use ① If the contents of the product are solid, you can use it as is. ② If the contents of the product are liquid, put it in the freezer for 10 minutes or soak it in cold water for 15 minutes, and use it after the contents have solidified. ③ When a person with a body temperature of around 36.5 degrees Celsius uses it for about 60 to 90 minutes, the contents of the product will melt and turn into a liquid. ④ You can also cool the product naturally just by storing it in a cool place below 27 degrees Celsius.