The Power Puff, with three times the insulation of the Light Puff and 1.5 times that of the BEER BOX, is a top-of-the-line model designed for cooling and heating. It uses Tyvek®︎ Silver and a high-loft type of batting (3M™️ Thinsulate™️) that is durable under pressure and resistant to flattening. The roll-top design prevents warm air from entering, and the aluminum-coated surface reflects heat, while the batting, which traps a large amount of air, provides insulation for cooling/heating. The regular size holds approximately six 500ml cans + α, a sufficient size for solo use. The S size holds approximately four 500ml cans + α, a convenient size that is neither too big nor too small. The Puff Thermal Sack achieves high insulation performance among compact soft-type coolers. Thinsulate™️ is a high-performance batting material made of a complex entanglement of ultrafine microfiber/polyester fibers. It excels in insulation/heat retention by trapping air, an effective insulating medium, and is also used in clothing and bedding. Regular Size Size: Approximately H36.5cm x W33cm x D12cm Weight: Approximately 88g Capacity: Approximately 4L Materials: Tyvek®︎ Silver / 3M Thinsulate™︎ / Others (The above numbers are approximate, please understand.) Naked Labo Neked Labo nakedlabo Cooler bag Insulated bag Cooling Heating Camping Mountaineering Minimal Ultralight