aeCoating NexPA-CF25 is one type 3D printing nylon filament with Co-extrusion skin-core structure and 25% chopped carbon fiber to improve its thermal and mechanical properties.This filament is highly abrasive, we strongly recommend printing with Tungsten Carbide Nozzle like the UndertakerPlease note: due to Carbonfibers and nylonmaterial print in an enclosure in a well ventilated room using proper protection as printing this material will likelyrelease harmful VOCs.