With the Colorpik digital ink pen, you don't need to buy hundreds color pens for drawing, by mixing ink to get millions colors we want, it brings huge benefit to customers, just ONE pen for dozens jobs, applications and scenes, which will save you much more money ! and storage space as well It also comes with a rechargeable battery which last for more than 24 hours from a single charge. with the refillable cartilage, you can refill the inks and use the pen for several years. Economic, Green, Repeated Use, which will save the world enviroment.