Write Your Secret Message: This magical invisible ink pen will help you write your secret message. Once your secret message has been written with this invisible ink pen it will disappeared, shine with the built-in UV light from the pens cover and reveal the secret message. Fun Activity for Kids: Ideal for a variety of fun activities such as party favor, treasure hunt, escape room party, birthday party, detective spy games, scavenger hunt, class breakout and so on. Gift Ideas: Perfect goodie bag fillers for New Year’s Day, Easter Day, Halloween, Thanksgiving Day, Christmas's Day and other parties. Dimension: 13 cm. Each pen is individually packed (As shown in picture). Colors of pen sent randomly. Popular among all age group: children, teens, students. Safe For Kids Toy: Harmless and odor free ink. Easy to push button for the light. Each Pens are quality checked before dispatch. Quantity : 4 Pieces individually packed (As shown in picture).