Features Measurement range 30 130dBdBAccuracy 1 5 dB reference sound pressure level 94dB 1kHz Dimensions 210 x 130 x 30MMFrequency response 31 5Hz 8 5kHzfrequency weighting AResponse time FastAlarm switch indicator Condenser microphone sensor Microphone 1 2 inch condenser microphoneDigital Display 3pcs 3 inch digital tube display threePower supply DC 5v 1A micro USBworking environment 0 40 degrees 32 degrees Fahrenheit to 104 degrees Fahrenheit 10 80 RHStorage of Temp and humidity 10 60C 10 70 RH Note This product has no switch function When you connect USB cable it will start When you take out the cable it will power off ThanksPackage Included 1 x SW 525A sound level meter 1 x DC 5v 1A micro USB cable Detail Pictures