Partners Session Drawstring ST Pet Bottle Keeper Color: Beige Unused since purchase, but stored after opening, so please refrain from purchasing if you are concerned about minor imperfections. There are marks on the stainless steel part. Optimal for keeping cold, a pet bottle holder. Insert a pet bottle drink into the double-walled vacuum tube to slow down temperature changes. The drawstring secures the pet bottle, allowing it to be used with various sizes. Heat Retention: 40 degrees Celsius or higher (6 hours) Cold Retention: 10 degrees Celsius or lower (6 hours) The temperature of the water inside the pet bottle after placing a 500ml pet bottle filled with 60 degrees Celsius ± 1 degree Celsius hot water (for heat retention) or 4 degrees Celsius ± 1 degree Celsius water (for cold retention) in a room at 20 degrees Celsius ± 2 degrees Celsius, closing the cap, setting it in the main body, placing it in the pouch, and leaving it upright for 6 hours. The vacuum layer between the stainless steel outer bottle and inner bottle blocks the outside temperature, enabling heat and cold retention!