Magic Invisible Disappearing Ink Pen with 6pcs Refills, File Security Ink Disappeared within Hours, Black The product is a invisible ink pen, it looks just like a normal pen, but the writing will disappear automatically and gradually in about 2 hours Make fun to your friend with this pen and good gift for your friends A great tool for magic trick The ink of the words that wrote down by this pen will disappear within hours Length: 14cm