... Lp , Leq , LE , Lmax , LminFrequency range 25Hz ~ 10KHzFrequency weighting A ,C, FlatTime weighting Fast , SlowDisplay 160x160 dot matrix display with back ... , 250Hz, 500Hz, 1KHz, 2KHz, 4KHz, and 8KHz. 1/3 Octave band center frequencies : (27 bands) 25Hz, 31.5Hz, 40Hz, 50Hz, 63Hz ... interface : RS-232 , 9 pin D-subPower 4 pcs of C size 1.5V (LR14) batteriesExternal DC power supply 6V, 1ABattery ...