Galaxy Audio CHECK MATE CM-130 - Manual (Page 10)

SOUND LEVEL METER
8
(4) Hold the instrument comfortably in your hand and point
the microphone at the suspected noise source. Read the
sound pressure level from the display.
(5) When MAX (maximum hold) mode is chosen, the
instrument captures and holds the maximum noise level
values indefinitely. The MAX function operates on all
settings, regardless of the response time, weighting, or
range.
Press the MAX button again to clear the MAX reading. The
“MAX ” symbol will disappear.
(6) Turn OFF the instrument and remove the battery when
not is use.