megasmile Black Whitening Manuel D'utilisation page 44

For each quadrant, move the brush first along the
internal tooth side over to the chewing surface, and
at last along the external tooth side.
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SENSITIVE Mode:
The upper light glows.
INTENSIVE Mode:
The two upper lights glow.
DEEP CLEANSING Mode:
The three upper lights glow.
POLISHING Mode:
All four lights glow.