System for adapting {HEAD ~ the resonant operation} of {TAIL ~ a personal care appliance} during the lifetime thereof 
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System for adapting { HEAD ~ the resonant operation } of { TAIL ~ a personal care appliance } during the lifetime thereof
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH