XIANQI Invisible Ink Pen, Spy Pen with UV Light Magic Marker Kid Pens for Secret Message and Party Goody Bag Stuffer 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 flavorless ink,healthy toys for your children!Smooth and colorful disappearing inks on T-Shirts,paper,skin and any surface!Permanent but washable! Christmas Party Goodies:Perfect for the RSVP's to wedding invitations;Goody bags for kids spy party;Make a fun party favor;Great goddie bag treat and brings you an amazing variety of fun applications.Birthday Gifts,Halloween Gifts,Christmas Presents for kids and friends. Please BE CARE small items:Children above 3 years. Color: red, yellow, blue, yellow, purple, black Size: 138*14MM Quantity delivered: 6 pieces