These invisible ink pens are a great way to write secret messages or notes that will only be revealed when held up to a uv light. The set includes 12 pens in a variety of colors, along with 12 goodie bags and 12 notepads. The pens write smoothly and dry quickly, making them perfect for everyday use. The invisible ink is activated by a black light, making it a fun and interactive way to write. These pens are perfect for kids, students, and adults who love to write and create secret messages. The set is also a great party favor or gift for any occasion.