The Extech 407766 1kHz 94/114dB professional sound calibrator is for 0.5 in. or 1 in. microphones. Calibrates and verifies sound level meter operation. Level position switch to select 94dB or 114dB with power on LED indicator light. Durable die-cast aluminum housing generates a 1kHz sine wave at 94dB/114dB to an accuracy of 5% (frequency) and ±0.5dB (94dB)/±1.0dB (114dB). Meets IEC standard 60942 1997-11.