Pioneer PDP-502MX Manual page 33

Special Installation (Embedding in the wall)
Methods of Securing: Basic methods of securing are shown below. Avoid blocking or covering areas aside from those
indicated by . The methods indicated by a large X-mark must not be used.
Before attaching the unit to fittings, double-check that the thickness and height of the fittings,
and the number of fixing bolts is correct.
(Also refer to 3.4.1 "Mounting to fittings".)
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