Take your creativity to new levels! The 3Doodler Start+ Eco plastic filament is compatible with the 3Doodler Start+ 3D Pen. Get the smoothest 3D drawing and doodling experience from out Start+ Eco Refills. Let your imagination go and bring any idea to life in 3D ! [Safe to Use] Designed completely safe for ages 6+ to use. The 3Doodler Start+ Eco plastic is a low-heat, BPA-free, and non-toxic filament that is biodegradable in a household compost and completely safe for kids. Safe to Doodle on almost any surface. [Hours of Fun & Play] One 6-inch strand can yield over 35 inches of doodles that means hours and hours of 3D drawing fun! It's safe to doodle on almost any surface, the material can be easily removed, though will adhere firmly to some clear plastics.