The Endevco model EM42AA handheld pistonphone delivers a highly stable sound source for accurate and reliable calibrations of measurement microphones, sound level meters, and other acoustic equipment. Compatible with Endevco and other standard 1/8-inch, 1/4-inch, and 1/2-inch measurement microphones, the pistonphone offers a sound pressure calibration level of 114 dB re. 20 μPa at a frequency of 250 Hz ±0.5%. Adapters are also included for calibrating 1/4-inch and 1/8-inch microphones. Each pistonphone is factory calibrated with an accuracy of ±0.08 dB re. 20 μPa and comes with a calibration certificate stating exact value and test conditions. Other features include a dual-color LED above the ON/OFF switch to indicate battery condition and operation. MEGGITT SENSING SYSTEMS, San Juan Capistrano, CA. (949) 493-8181.