Spy Pen:The ink is invisible after you write with it,unless you light on the cap blacklight to see the secret message perfectly. Invisible Ink Pen: Harmless and tasteless ink, healthy toy for your kids Smooth and colorful disappearing inks on t-shirts, paper, skin and any surface Permanent but washable With 14 Pcs in the bag, you can easily host a kid's birthday party favors stocking stuffer, treasure hunt,escape room,or classroom activity complete with invisible ink clues Exciting Spy Activities For Kids: Kids will love these pens. Kids love using this kind of pen to keep their secret and play detective spy games. Invisible pen brings you an amazing variety of fun activities. From Surprise birthday parties, to revealing a top secret message to their parents or grandparents. Great Gift for Fun Party Goodies:Perfect for wedding invitations; Make a fun party favor; brings you an amazing variety of fun applications.Birthday Gifts,Halloween Gifts,Christmas Presents for kids and friends.Kids love using this kind of pen to keep their secret and play detective spy games. Schools, teachers can buy it for students for a school activity.Add it for any surprise gift bag or as a kids stocking stuffers. Package includes: 14 invisible magic pens,built-in UV lights. Batteries included and installed. Be careful with small items: children over 3 years.