This is a bulk purchase, and these are the ones I didn't use. I hope someone who needs them can use them. The following is an excerpt from the seller's page: Wear it around your neck for outdoor activities and sports! ・It won't get your skin or clothes wet due to condensation, keeping you cool and comfortable for a long time! ・It can be used repeatedly for heatstroke prevention in various situations such as at home, camping, when sleeping, and during sports. It changes to a cool solid state at 28°C or below, so refrigeration is not required. ※Refrigeration can shorten the cooling time. It will liquefy in an environment of 28°C or higher, but it can be used repeatedly by refreezing it. Product size (package size) H18.5cm x W13.5cm x D2.5cm Body size 14cm x 15.5cm x 2.5cm thick Inner circumference: 32cm Material TPU (Thermoplastic Polyurethane), PCM (Octadecane) Cooling time目安 (approx.) Freezer: 10 minutes Tap water: 30 minutes Environment below 28°C: 3 hours