WE-CMS Common Mode SMD Bead Würth Elektronik WE-CMS Common Mode SMD Bead provides EMI/RFI Suppression with 200Ω impedance with 25% tolerance. This ferrite bead offers a max. DC current of 5A and max. DC resistance of 3mΩ. The Würth Elektronik WE-CMS Common Mode SMD Bead is ideal for power supply systems, symmetric data lines, common mode interference, and power electronics.