3Doodler Flow Premium 1.75mm Filament 3D Pen Refills are crafted to bring your 3D printing and art projects to life with vibrant hues and stunning detail. The 3Doodler Flow Pen Refill Spools offer a selection of 20 vivid colors to transform your creative ideas into tangible works of art. Each spool, measuring three meters in length, provides extended opportunities for creativity.