These are 20oz Straight glow-in-the-dark tumblers, to activate the glow they need to be under light for 2-4 mins for them to glow. They can be charged in direct sunlight or by UV light. A regular houselight doesn’t give them the proper charge. Steel Custom Made 20oz Tumbler Double Wall Insulated“Custom Made - One of a Kind - Smoke-Free Home - Straw...Clear Slide Lid Included”The tumbler is made of 18/8 304 food-grade stainless steel, double-walled, which can keep the water hot or cold for hours.The image is printed directly onto the tumbler’s clear coat using a heating process called sublimation.The image will not crack, peel or fade. Not vinyl or epoxy. The Image is bonded to the tumbler These Tumblers are hand-made by me...(All my Tumblers are made to order..so the tumbler you will receive might be slightly different from the one in the pics)Handcrafted by me, by hand "so the tumbler may have small imperfections."I'm only human after all....(any glare or light flashes in the photo are due to my camera)