This is a cooling pack to put inside hats or helmets. It keeps your head cool. The PCM (Phase Change Material) has a melting point of 22°C (72°F). Many similar products have a melting point of 28°C (82°F), but this one provides a greater cooling sensation. S size, 18cm (7 inches) in diameter. Approximately 95g (3.4 ounces). It's thick, so I think it lasts a long time. It can be folded in half, making it compact for carrying. I've bought various similar products, but after using them a few times, I've decided to mainly use other products, so I'm offering this one to someone who can use it. It will be sent in a waterproof bag via anonymous shipping. If you purchase multiple items, I will discount the shipping cost, so please consult with me before purchasing. #acha's miscellaneous goods list Cool Head Pad Flowna Cap Hat Cooling Pack Head Cooling Pad Cool Pad Heatstroke Prevention