Features: 1. The shell of the invisible ink pen is made of high-quality PP material, which is not easy to break, can be used for a long time, and is durable. 2. Suitable for opaque writing, decoration, graffiti, painting or coloring, even on dark and colored paper. 3. Very attractive, adding creativity and fun to the items. Due to the metallic luster of the ink, the letters and marks produced will be both obvious and eye-catching. 4. With the built-in ultraviolet light, children can write messages to each other, which is invisible, and the text will appear when the ultraviolet light on the pen is turned on. 5. Note: You can write on most surfaces, but whether you can stay on the surface depends on the type of material you write. If you write on paper, it can stay forever; if you write on metal or plastic, it may not last long, because it can be easily erased due to the properties of metal and plastic. Notice: 1.Actual color may be slightly different from the image due to different monitor and light effect 2.Please allow 1-3cm deviation due to manual measurement Description: Material: PP Size: 131mm*20mm*18mm Power supply mode: 3 AG3 button batteries replaceable Color: red, yellow, blue, green Package List: 4 x Invisible Ink Pen