applicable stangdards iec pub 60651 type2, ansi s1.4 type 2 digital display 4digital lcd, 0.1db resolution,up-dated every 0.5s measurement level 25~130db measurement frequency range 31.5hz to 8 khz frequency weighting a and c time weight fast and slow microphone 1/2 inch electret condenser microphone measurement level range 5 ranges in 10-db step:25~80db 30~90db 40~100db 50~100db 60~120db 70~130db quasi-analong bar indicator 1-db steps,60db display range ,up-dated every0.125s display warning function overrange indicator underrange indicator ov displayed at the upper limit un displayed at the lower limit manual data memory capacity 99 sets analong ac/dc output 2vrms (at full scale), 10mvdc/db power supply one 9v battery (006p to iec6f22) ac adapter battery life about 50 hours weight approx.310g