, mugs are safe to use for any beverage We suggest, please place mugs upside down in the freezer for 2-4 hours The freezer gel is safely between the double of the glass, it ’ s not for touch your drink Mug only, other accessories demo in the picture is not included The unique gel shows a frosty appearance between your beverage and the mug It ’ s not for touch your drink, keep your drinks original flavor, which produces a quickly ice-cold effect Double-walled insulation filled with crackle gel, the mugs will keep your drinks cold rapidly! NOTE: PLEASE KEEP THE MUGS No LIQUID AS POSSIBLE NO WATER WHILE FREEZEING IN THE REFRIGERATOR