Athena, Attica, AR tritemorion. ca 479-404 BC. 6 mm. 0.5 g.

Helmeted head of Athena right.
A-E (retrograde) Q surrounded by three crescents. 

BMC 183.

With permission of cngcoins.com, auction 85, Lot 355, Sept. 2010.

There are a number of variants of the reverse: 
A-E (retrograde) Q = BMC 183
A-Q E (retrograde) = BMC 184-186; Agora 21a
A-E Q = BMC 187-190; Agora 21b; SNG Cop 57-58
A-Q E = BMC 191