I managed to pick this small item of militaria up earlier this year at a Toowoomba show. I believe it to be a kit bag lock for a soldier's duffle bag, probably from the World War II period or earlier. It is made of brass and in good working order.
My understanding is that it would be threaded through the eyelets in the top of the kit bag, drawing it closed. A small padlock would then be secured through the hole to keep it locked tight. It would then act as a handle as well as a lock for the kit bag.
When I showed it at a recent bottle club meeting, there was some conjecture over whether it was a piece of militaria or something used to secure mail bags. I believe it to be militaria after seeing a similar one at the Harrisville Museum two weeks ago labeled as being from an Army Kit Bag (see photo below). My reasoning is that anyone donating this to the museum would have known whether their ancestor was either a soldier or a postman. I did see a mail bag lock at the Templin Historical Village, Boonah earlier the same day. Unfortunately I don't have a photo of it. It did however have a slightly different action and shape.
I can highly recommend a visit to both these museums and having an enjoyable look around the surrounding countryside.
I don't really collect militaria but couldn't resist picking up this interesting little bit of history for my collection.