The DBchecker™ is a SOUND LEVEL METER that tests audible appliances for the public operating mode of an emergency voice/alarm system. Easy to use, it conforms to ANSI S1.4 Type 2, which is required by NFPA 72. Measuring levels range from 32 dB to 130 dB, at frequencies between 31.5 Hz to 8 kHz. Unit has two equivalent weighted sound pressure levels (A and C) and displays with a resolution of 0.1 dB on a four-digit LCD screen. 9V alkaline battery included.