SDR SMD Electromagnetic Buzzer TDK SDR Electromagnetic Buzzer is suitable for surface mount process (SMD) and is composed of high-quality parts (yoke and magnets) to provide a high output level of sound pressure (min. 88dB) in spite of its compact size. The TDK SDR Buzzer is Lead (Pb) free with a rated nominal input voltage of 3V, an operating voltage of 1V to 5V, and an operating temperature range of -40°C to +85°C.