Storch ProDist compact plus Original Instruction page 84

For measurements from one corner, unfold the try square
until it latches; then push the try square against the corner
with slight pressure. Make sure that the measuring plane
is set to "End piece".
Changing the unit (m, ft. In, ft + in)
Hold down the
Sound on/off
Hold down the
84
button to change the units.
button to switch the sound on/off.
Original instruction