Permits choice "A", "C", "F" weighting and "Fast"/"Slow" response times. Offers 4 measurement parameters: Lp (sound level); (Equivalent Continuous A Sound Level); Lmax (Maximum Sound Level) and LN (Percent of all readings over alarm value set). DC output:10 mV/dB Can memorize 30 groups of measurement results and measuring conditions. Auto range selection and digital display with no guessing errors. Use USB/-232 data output to connect with PC. Provide Bluetooth data output choice. Sound Level Meter SL-5868P Spec: Widely used to test the sound level of environment,machinery,vehicle, ship and other noise. For industrial environmental protection,construction, health care, teaching and research department. Standards:IEC 651.2, ANSI 1.4.2 Paraments Measured: Lp - Sound Level - Equivalent Continuous A Sound Level Lmax - Maximum Sound Level LN - Percent of All Reading Over Alarm Value Set Resolution: 0.1dB Accuracy:1dB Frequency Weighting: "A" / "C" / "F"*(Flat) Time Weighting: Fast (125 ms)/Slow (1 Second) Microphone:1/2 Inch Electret Condenser Type Memory: 30 Group with Measuring Conditions Calibration Signal Built in: 94dB at 1k Hz(sinusoidal) Frequency Range: 20Hz-8kHz Alarm Value Set: 30dB-130 dB Alarm Output: LED Optional Relay Contact(NC) Indicator: Low Battery Indicator Power Supply: 4x1.5V AAA Size (UM-4)Battery External DC Power Supply: 5V, DC, 100mA Dimensions: 236mmx63mmx26 mm Weight: 170g Color:As Shown Material:Metal+Plastic Package Contents: 1 * Handheld sound level meter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.