BLM18PG121SN1D is a ferrite bead manufactured by Murata. It is an EMI suppression filter made with a 0603 size chip, and is rated for a resistance of 120 ohms. It is designed to reduce interference from RF and other electromagnetic sources, and works to attenuate high-frequency interference while allowing signals to pass at normal frequency ranges. The BLM18PG121SN1D is rated for an operating temperature range of -55 °C to +125 °C, and is suitable for use in automotive and other harsh environments.