Stainless steel tumbler starts off white, but changes color when placed in sunlight. Once charged in UV light, it will also double as a night light as it glows in the dark! Perfect gift for a loved one, or vacation group to enjoying a delicious hot or cold beverage. These were created for my girls vacation group. they kept our drinks cold in the hot Mexican sun! Though, if you wear sunscreen, wash your hands before handling mug, as it will affect its ability to absorb UV light (great for your skin, bad for the tumbler). These tumblers are double-walled to keep beverages cold or warm for hours, and made of high quality 304 stainless steel. I do not use epoxy on my mugs or tumblers. The images are heat and pressure transferred into the surface itself. It will not crack, peel, or fade if left in a hot car or frozen ski bag. Each tumbler comes with dust-proof slide lid, plastic color matching straw, tumbler care instructions. Choose from 5 different colors (pink, purple, orange, light blue, dark blue). To personalize, message me with names and event title (to replace “Vacation Cronies 2023” if preferred).