Landtek Instruments Professional Digital Sound Level Meter 30 to 130db with Bluetooth (Optional) Standardisation: IEC651 Type 2, ANSI S1. 4 Type 2 PC interface: Bluetooth + CD Software (Optional , not included , cost USD50 extra , contact seller if needed) Support WIN 8 ; Function: Lp, Leq, Lmax, LN. with Frequency range: 20.0 to 12,500Hz Frequency range: 20.0 to 12,500Hz / Frequency weighting: A, C and F (Flat) Alarm: electron, adjusable, 30-130dB set, LED and optional relay contact (NC) output Built-in calibration signals: 94dB at 1kHz (sinusoidal) Product description Great for noise pollution monitoring,factory,office,traffic, home theater setup,health and safety compliance,vehicle noise testing and o system. Features Transfer data via Bluetooth connection Filters-out unwanted signals Bar graph & Over/under load Indication A freq. weighting (general sound level measurements), C freq. weighting (checking low-frequency content of sounds) AC/DC analog signal output for connecting to freq analyzer level recorder,FFT analyzer and graphic record Factory pre-calibrated Specifications Measuring Level: 30-130dB(A), 35-130dB(C) Level Range: 30-80dB ; 50-100dB ; 60-110dB ; 80-130dB ; 30-130dB PC interface: Bluetooth+CD Software Accuracy: +/-1.5dB (under reference conditions) Resolution: 0.1dB Range: 31.5Hz-8.5KHz (Frequency) ; 50dB/100dB (Linearity)50dB scale at 1dB step for monitoring current sound pressure level Sample Rate: 20times/sec Display: 4 digits AC Signal Output: 0.707Vrms at FS output impedance approx. 600(ohm) DC Signal Output: 10mV/dB, output impedance approx. 100(ohm) Time Weight: FAST / SLOW Mic: 1/2" Electronic Condenser mic Max hold function Environment 0-40°C, 10-80%RH (Operating) ; -10-60°C, 10-70%RH (Storage) Power: 4xAA 1.5V alkaline batt (included) or DC 6V 100mA (max DC9V) (not incl.) Batt Life: About 30hrs (alkaline batt) Size: 256x70x35mm Weight: 230g (excl. batt) Set Includes 1 x Sound Level Meter 1 x Windscreen / Sponge Ball 1 x Shock Absorbent Carrying Case 1 x English Manual 1 x Standard Packaging Box Optional Accessories (Contact Customer Service ) (Optional , not included , cost USD50 extra , contact seller if needed) 1 x CD Software 1 x Bluetooth