Extech 407790-NIST - NIST Calibration Certificate - sound level meter and data logger features: Type 2 integrating sound level meter with Octave and 1/3 Octave Band Real Time display; 160x160 dot matrix backlit LCD displays Leq, LE, Lmax, Lmin, and Lp; Built-in memory stores up to 12,280 records in SLM mode and 1024 data points in 1/1 or 1/3 octave mode; Stored data can be easily transferred to a PC via RS-232 interface and analyzed using software and cable provided; A, C, and Flat weighting with Fast/Slow response time; 25Hz to 10kHz frequency response; Meets ANSI and IEC Type 2 standards; Real time clock with Year, Month, Day, Hour, Minute, and Second display.