Bosch Smart System Magnet Magnetic Missing a magnet for your Bosch drive unit? You can easily replace it. The Bosch Smart System Magnet comes in either a rim magnet or hub magnet variant. These are designed for specific types of Bosch systems, so make sure you get the one that is right for your setup. Features Bosch wheel rim magnet: designed for BRM3400Bosch magnet 6-hole: designed for BDU3XX, BDU4XX, and The smart system Rim magnet part number: EB11. 200. 0156-hole hub magnet part number: 1270. 015. 728 | Bosch | Smart System Magnet Rim (Valve Stem)