The unit uses a 12-Vpp sine wave to produce 103-dB sound output in the frequency range of 3.3 ±0.5 kHz. The alarm operates over a temperature range of 40 to 70°C and is housed in a 46.5-mm-diameter housing made of black PA66 material. Transducers USA Inc., 1400 Howard St., Elk Grove, IL 60007, (888) 921-6400,