Physique Tea Beautiful Color Changing Coffee and Tea Travel Thermos | 11oz Blue Gold and White | Perfect Present Wrapped in Silk Lined Box and Gift Bag Flower on thermos changes colors depending on the temperature of the liquid being transported. Purple flower means cold and pink flower means warm. BPA and plastic toxin free, this ceramic tumbler is a great alternative to traditional travel mugs and thermoses. Silk lined gift box creates an incredible presentation when purchasing as a gift. Perfect idea for Mothers Day! Beautiful but also functional, this thermos will will keep your drink of choice hot or cold for hours.