Multifunction Luminous Light Invisible Ink Pen UV Money Checker Kid Drawing Learning Pen 20ml Feature: Quantity: 1PCS Boys Girls Great Party bag fillers toys for kids. Writes on most surfaces. With built in Ultra Violet Light, Kids will write plenty of secret messages to each other and its not visible to the naked eye turn the UV light on the writing appears Note: You can write on most surfaces, but whether it can stay on the surfaces It depends on what kind of the material you write on. If you write on the papers, it can stay on permanent; if you write on the metal or plastics It may couldn't last long, because it will be erased easily due to the characteristic of the metal and plastics. Size:about 13CM Material:Plastic Package Content: 1X Secret Message Pen This pen's innovative design can help you overcome anxiety and bid farewell to difficult choices. This pen adopts a silent bearing design, which is quiet and noiseless. The size is, the writing is smooth, and the feel is comfortable. Difficult choice, indecision, solve it in one fell swoop, bring it home quickly High quality materials: Our pen is made of high-quality and environmentally friendly materials, which are sturdy, durable, and very convenient!