A rotatable fastener has a head portion with an axially facing ring gear engageable with {HEAD ~ a complementary gear} of {TAIL ~ a drive tool} 
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A rotatable fastener has a head portion with an axially facing ring gear engageable with { HEAD ~ a complementary gear } of { TAIL ~ a drive tool }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL