Kenwood KDC-3011 Instruction Manual page 28

Installation
@ Screwing the Faceplate on the Unit
(KDC-3011/2011S only)
lf you want to fasten the faceplate to the main unit so that it
does not fail off, screw in the provided screw (#4 x 16 mm) in the
hole shown below.
ACAUTION
Never insert the taptite screw (a4 x 16 mm) in any other screw
hole than the one specified. If you screw it in another hole, it will
contact and may cause damage to the mechanical parts inside
the unit.