3D printing pen filament refills PCL plastic filaments, has good flexibility, impact resistance and durability, is suitable for making some small handicrafts and painting, for beginners or craftsmen who like to make small crafts. Filament Diameter: 1.75mm; Pack of 10 colors 3D Pen Filament, each color 16.4 feet, total 164feet. The melting temperature of low-temperature(less than 100C/212F)3D printing pen PCL filament is much lower than that of traditional PLA and ABS filament, which greatly reduces the temperature of the pen tip. Put the refill filament into the feed opening at the end of the 3D printing pen, and the filament should be against the front end. Then press the discharging button on the side of the charging port, and wait for the 3D printing pen to heat up the filament before creating. PCL filament that has not been used should be stored in a dry and sealed manner to extend its service life. PCL material is not resistant to high temperatures.