Samsung Mono & Stereo HM3500 Guide Rapide page 11

Depending on what ear you are going to wear the headset, simply remove and
replace the ear hook.
 Left  Right
You can also use the ear rubber instead of the ear hook. Remove the earpiece cover
and attach the ear rubber. Then, rotate the ear rubber left or right slightly depending
on what ear you are going to wear the headset. If it does not fit your ear, replace
it with the other.
 Left  Right
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