High Quality: Quality 3D insert allowing a good finish. The inserts are stable and cling strongly to the plastic allowing easy screwing. the opposing spiral knurled nuts provide high and balanced torque and tightness as well as high traction. 3D Printing Parts: Using ultrasound or heat (soldering iron), the Einpressmuttern can be easily integrated with a blind or through hole. Stable and Durable: The inserts are made from the highest quality brass, offering excellent corrosion resistance and excellent thermal conductivity for long-term use and insertion easy. Plastics Application: Used with a soldering iron to join and join 3D printed parts in PLA and PETG. The most suitable plastics are PLA, PETG, ABS, ASA, PPS, CPE, PP, etc. Includes Quantity: Package includes 330pcs knurled threaded insert nuts; Size includes: M2 M3 M4 M5.