Models for rapid prototyping or educational purposes. Not functional without the rest of the motor - stator body and rotor with magnets, winding, axis etc. I printed the 2820 stator from Iron-PLA by Protopasta and once I winded it, it worked but the motor had no torque and once it heated above 60°C the stator deformed and motor stopped working. The smaller stators are hard to make them work without using the conventional silicon steel layers.