The Extech 407790A Real Time Octave Band Analyzer is an auto ranging Type 2 integrating sound level meter that features 1/1 and 1/3 Octave Band real-time noise display and analyses. The 407790A offers five measurement parameters: SPL (Sound Pressure Level), Leq (Equivalent Continuous Sound Pressure Level), SEL (Sound Exposure Level), Lmax (Maximum Sound Pressure Level), and Lmin (Minimum Sound Pressure Level). The built-in memory stores 12,280 data records in sound level mode and 1024 records in Octave mode. The stored data can be easily transferred to a PC with the 407790A software and USB cable. This meter permits choice of ‘A’, ‘C’, or Flat ’Z’ weighting and Slow / Fast /impulse response times. AC and DC analog output signals are available for chart recorders and other external recording devices.