Invisible Ink Pen: Write your secret message with these magical UV pens! It's invisible unless you shine UV light on the cap to perfectly reveal the secret message. (Invisible pens come in red, black, yellow, green, blue, purple, and pink, and the ink is transparent). p>SAFE AND HARMLESS: ABS plastic + button battery (included), the invisible pen with UV light is non-toxic, harmless, and odorless, you can rest assured to let your children play. Pay attention to small items: suitable for children over 3 years old. Children under 3 years old should use it under adult supervision.7 Colors: The invisible ink pen with UV lamp has 7 colors on the outside, but the ink is monochrome.All Occasions: Magic pens can be applied to t-shirts, paper, skin, and all smooth surfaces. We can get creative by writing, sketching, and drawing secret messages.Creative Toys for Kids: Kids can use the spy pen to keep secrets and play spy detective games. Kids can surprise families with secret cards for Mother's Day, Father's Day, Halloween, Thanksgiving, and Christmas. Schools, teachers can buy it for students for school activities.#