This is an integrating sound level datalogger, model 407780. It has programmable integrating time, provides precise linearity over a wide range (100dB), and displays Leq, SEL, SPL, MAX-L and MIN-L measurements. Response time (FAST, SLOW and IMPULSE) and frequency weighting (A and C) are programmable. The analog output (AC and DC) can be used with headphones, chart recorders or other devices to store data. The 407780 with PC Interface and real-time calendar clock datalogs (stores) up to 32,000 readings for later transfer to PC. Careful use of this meter will provide years of reliable service.