... series precise impulse sound level meterIt meets IEC 61672 standard and the first class sound level meter standard of JJG188-2002 sound meter ... (linearity)Frequency range10Hz-20kHzFrequency weighting A,C, linearityDetector characteristicsTrue effective value, peak valueTime weighting Fast (F), Slow(S), Impulse ... 5dB, LED Power DC 6v, 4 pieces of 1.5v batteries, with external DC voltage input holeWith AC ...