SOUND LEVEL METER The Testo 815 and 816 sound level meters can measure noise levels of various objects including photocopiers, printers, and exhaust fans. Both Testo units feature a measurement range of + 30 to + 130 dB( A) and the 815 meter does so with a Class 3L accuracy ( ± 1.5 dB( A) ) and the 816 meter offers a Class 2L accuracy of ± 1.0 dB( A) . Other features of the Testo 815 and 816 sound level meters include a detachable microphone to avoid measurement errors, digital noise suppression for exact measurements and unit calibration via the keypad. This lightweight unit, weighing 170 grams, provides you with a versatile sound level measurement device for multiple environments - office space, laboratory, production floor, and others. The Testo Model 816 also features a bar graph display along with automatic range switchover. The Model 816 is equipped with DC output with 10 mV/ dB to connect recorders or dataloggers. The Testo 815 sound level meter has an accuracy of class 2 and is the ideal instrument for daily use. Whether it is for air conditioning or heating, disco noise, machine noise or noise in combustion systems, the Testo 815 is the ideal partner. Features:  Accuracy class 2 to IEC 60651 Easy to adjust ( adjustment screwdriver included)  Frequency weighting to Characteristic A and C Maximum and minimum value memory Built-in tripod knuckle screw ( ¼ inch)  Switchable time weighting Fast/ Slow Mains unit connection ( optional)  Calibration certificate ( optional)