Sony HT-A9 Help Manual page 21

(e) Approx. 7.35 mm (approx. 19/64 in)
Peel off the cover on the rear of the speaker with a safety-pin, etc.
3
Cover
Hang the speakers by confirming the type of the speakers.
4
Check the label on the bottom of the speaker.
Front left
Front right
Rear left
Rear right
Note
Keep the cover that is peeled off in step 3 for use when you do not mount the speaker on a wall.
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