Our heat sensitive photo mugs are fantastic 'magic' fun. The heat change mug will feature your photo and message, underneath a black heat sensitive coating. The heat change mug coating 'disappears' when the mug is hot to reveal your photo and message (which will wow everyone of course!). Please note, some designs may still be visible when the mug is cold. If you are planning to purchase a large number of these we recommend ordering a "tester" mug first to ensure satisfaction. Due to the heat sensitive coating we recommend you hand wash these heat changing 'magic mugs'