Prokit's Industries MT-4018 - Manual (Page 10)

Under the state of auto-range measuring,
symbol AUTO displays and the micro- controller
selects a proper range to measure sound
automatically. The range is displayed on top of the
screen.
Under the state of manual-range measuring,
symbol MANUAL displays. You can press button Up
or Down to choose the proper range. The range is
displayed on top of the screen.
3. UP
key
Under the state of manual-range measuring, You
can press button Up or Down to choose the proper
range.
When LCD appears OVER symbol, it indicates
that the range is low, you need to press button Up to
set higher range until no OVER symbol.
4. DOWN
key
Under the state of manual-range measuring, You