TRADE ONE Double PCM Cool Neck Ring (28°C) M+L Size, Mint Green Brand new, unused. This neck cool ring uses a special material that repeatedly releases and absorbs heat and cold, providing long-lasting cooling! M and L sizes are available, fitting neck sizes of approximately 30-38cm. Unisex. Can be used repeatedly for heat対策 in various situations such as at home, outdoors, while sleeping, commuting, sports, etc. 【Reusable】 No charging or batteries required! It's eco-friendly as it can be reused by cooling it down. 【Mild Coldness】 The cooling power lasts for about 1 hour after solidification. Even though it looks frozen, it's not too cold like ice, so it's comfortable to touch your skin. 【New Material That Solidifies Naturally】 Uses PMC material that solidifies in environments below approximately 28 degrees Celsius. It has the characteristic of repeatedly releasing and absorbing heat and cold, making it possible to maintain a comfortable temperature by sustaining the cooling sensation. 【No Condensation, Stays Dry】 Unlike regular ice packs, it's less likely to condense when melting, so your clothes won't get wet. 【Specifications】 Suitable Neck Size: Approximately 30-38cm ● Cooling Method: Cooling lasts for approximately 1 to 1.5 hours after solidification. (Based on our research) * Duration when worn around the neck in an environment below 28°C. * Cooling time and duration vary depending on the environment. Freezer: about 20 minutes, Refrigerator: about 60 minutes, Cold water: 30 minutes or more (water temperature below 20°C), Cold air: 60 minutes or more (set temperature below 28°C)