Decibel Meter AZ-8922 1).30-130dB.Backlight 2).RS-232 for Optional ... IEC 651, Type 2 Class Decibel Meter AZ-8922(30-130dB) with Free Shipping AZ-8921 & 8922 DIGITAL ... Multi-Freguency calibration to ensure quality stable.SPECIFICATION Auto range :30-130dB. Big LCD :42x64mm. Measurement level range : 6 ... ranges in 10-dB steps:30-80dB, 40-90dB, 50-100dB, 60-110dB, 70-120dB ...