A. [Safer and healthier materials] Compared with the 1.75mm ABS/PLA filament refill for 3D pens, the PCL filament has a relatively lower melting point of only 70°C, reducing the risk of burning hands. In addition, the PCL filament refill is derived from renewable plant resources. When injected into the 3D pen, it hardly produces pungent odors, is non-toxic, odorless, non-irritating, and biodegradable. B. [20 colors] The 3D pen filament refill set contains around 20 different colors. You can use them to depict the creativity of 3D art masterpieces and make your masterpieces glow in the dark. This is a suitable 3D pen for children and art lovers. They can use it to DIY what they want and let children enjoy the fun in handicrafts and painting. C. [Ultra-smooth] The PCL filament for 3D pens uses low-temperature release technology. The high-precision PCL filament with a diameter of 1.75mm ensures that your 3D painting is relatively smooth, with little oil residue or air bubbles, and is less likely to clog. D. [Universal compatibility] It is compatible with many 3D pens/3D printers on the market, but may not be suitable for 3Doodler pens. E. [Enjoy the fun of creation] This 3D printing pen filament refill is a good gift for children, which helps to improve their spatial thinking ability and cultivate creativity, imagination, and artistic skills. In addition, it is also a way for parents and children to spend happy time together and enhance their relationship. F. PCL filament refill - Size: Each roll is approximately 3.0 meters long. - Material: PCL. - Color: Random colors. Around 20 colors are randomly matched and usually cannot be specified. G. Package contents: 1 set of PCL filament refills for 3D printing pens. Only the above package contents are included, and other products are generally not included. H. Precautions: Light irradiation and different monitors may cause some slight differences between the colors of the items in the picture and the actual objects. The allowable measurement error is about +/- 1 - 3 cm.