Beware! Reproduction RAF Air-gunners' winged-bullet brass arm badges 1923-1939 are being misrepresented as Australian Army helicopter gunners' badges. There was no such badge in the Australian Army. The RAF badges were worn until mid 1940 (latest) and sell for about $60-80, they also have three lugs on the back. Reproductions go for about $10 and have two lugs. Don't be sucked in by artificial ageing and 'waffle' in the description.
Do your homework and good collecting . . .