A good upgrade for your classic mini milling machine. I found a different company that makes a stable polycarbonate carbon fiber reinforced filament. The gear is designed and made with pockets in each valley that act as decompression zones while the gear is in motion. This greatly reduces the noise created during moderate and high rpm usage. Good for use in gunsmithing, automotive, jewelry making, R/C hobbies, etc. It's very easy to change the gear out. Remove the 4 bolts for the motor and remove the Phillips screws holding the gear exposed. Pull the old gear out, press the new gear in and get back to machining.