The BLM18RK471SN1D is an EMI filter bead manufactured by Murata. It is a 4-terminal, low noise, Ferrite-core bead of material that can suppress high frequency noise on signal and power lines. It is constructed of a ferrite core wirewound construction with low characteristic impedance, and is designed to suppress electromagnetic interference of up to 2GHz in range. The characteristic impedance is 470O, specifically designed to aid in impedance matching and improving signal voltage definition. The bead is suitable for high frequency applications such as GSM, WCDMA, LTE, NFC, and more. It can also be used as a termination resistor or RF choke for power supply systems.