Developer Unit Gear Kit For MP4000 4000B 4001 5000 5001 5000B Magnetic Roller Bearing B0043059 Gear Seal The Developer Unit Gear Kit is designed for the MP4000 series, including MP4000, MP4000B, MP4001, MP5000, MP5001, and MP5000B models. This kit ensures the printer operates efficiently and maintains print quality. The magnetic roller bearing and gear seal are made from materials, providing consistent performance and extended service life. This kit offers a practical solution for replacing worn components without requiring a full machine overhaul, helping to reduce long-term maintenance costs. The kit is tested to match the performance of manufacturer parts.