[HEALTHIER MATERIAL] Compared to ABS/1.75mm refills, PCL filament with a lower melting temperature of 70°C eliminates the risk of hand burns. In addition, PCL filament refills are 100% derived from renewable plant resources, do not create a pungent odor when infused, are non-toxic, odorless, non-irritating, and biodegradable. [30 COLORS] Refill pack with 30 different colors for your 3D artwork and makes your masterpiece glow in the dark. A great gift for art enthusiasts to DIY what they want, and encourage children to have fun with crafts and drawing. PCL filament for low-temperature release technology and high precision PCL filament 1.75mm diameter makes your 3D drawing very smooth without oily residue or clogging. [UNIVERSAL COMPATIBILITY] Compatible with most 3D pens/3D printers on the market, not suitable for pens. [ENJOY THE FUN] These 3D printing pen filament refills are gifts to improve their spatial thinking, cultivate creativity, and artistic skills. Also a great way for parents and children to spend happy time together, strengthening the bond. Color: random color, cannot accept the specified color. Material: PCL. Size: Length of each spool: 5M. Package contents: 30 x 1.75mm. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be a little different from the real thing. The allowed measurement error is +/- 1-3 cm.