Please ensure to consider the type of wall you are mounting your speaker brackets on.
It is your responsibility to check the bracket is fitted properly to a suitable wall and to use suitable equipment to find battens/studs and ensure there are no hidden wires or dangers behind where you intend to drill.
Do not mount onto drywall, plasterboard or partitioning walls unless screws are fixed into a wooden batten/stud. When fixing to brickwork or suitable masonry walls use wall plugs and screws.
Check the strength of the installation before installing the loudspeaker and if you are unsure please consult a qualified contractor.