The CM-140 is small in size, low cost high performance and features a MAX/MIN function, level range display, AC signal output, resolution 0.1 dB, IEC 651 Type II, ANSI S1.4 TypeII, Electret condenser microphone, Accuracy: ±1.5 dB ( ref 94dB @1KHz ), Level Range: Lo = 35 ~ 80 dB Med = 50 ~ 100 dB Hi = 80 ~ 130 d, A, C frequency weighting, fast, slow time weighting, AC signal output, 50dB dynamic range, 9V battery life of 70 hours, has dimen...