SOUND LEVEL METER The Amprobe SM Series of Sound Level Meter is designed to meet the measurement requirements of Safety Engineers, Health, Industrial safety offices and Quality Control in various environments. It offers two types of measurements: A and C weighting. The A weighting is for general noise sound level and the C weighting is for measuring sound level of acoustic material control in various environments ( ie 94dB 1 kHz etc...) . The SM-10 conforms to the IEC651 Type 2, ANSI S1.4 Type 2, and JISC1502 requirements for Sound Level Meters. Which means the SM-10 uses two different weighting filters required by the IEC 651 and ANSI S1.4 Type 2: the A-Weighting and the C-Weighting audio filtering. The SM-20 conforms to the IEC651 Type 2, ANSI S1.4 Type 2, and JISC1502 requirements for Sound Level Meters. Which means the SM-20 uses two different weighting filters required by the IEC 651 and ANSI S1.4 Type 2: The A-Weighting and the C Weighting audio filtering. Features:  Designed to meet the measurement requirements of Safety Engineers, Health, Industrial safety offices and quality control in various environments. A and C weightings for checking compliance with safety regulations as well as acoustic analysis Measuring ranges: A Weighting 30~ 130dB, C Weighting 35~ 130dB Frequency range: 31.5Hz~ 8KHz Display with 0.1dB steps on a 4 digit LCD Slow ( 1 sec) and fast ( 125ms) response settings to check peak and average noise levels MAX/ MIN recording Internal memory, 14, 000 records ( SM-20 only)  Recording intervals from 1 second to 8 hours ( SM-20 only)  PC computer download capabilities ( SM-20 only)  Data Hold to freeze reading on digital display CE, designed to meet IEC651 Type2, ANSI S1.4 Type 2