I found this strange looking bit in a bit set of uncommon bits, including Security Torx, hexalobular, tri-wing, spanner head, 12-point flange, Torq-set and others. It's the only one that I could not identify, what is it for?
My first thought is that it might be intended to be a wing nut driver of some sort, but those are usually hollow cylinders with slots for the wings.
Ah ... sure enough, it's described as such in this Ebay ad:
It can also be used for fastening the 'eye' of hook and eye fasteners into wooden frames.
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