So today I picked up some items from an old farmhouse in rural NSW Australia and the owner told me his dad who fought in WW1 brought these back from his tour. The owner was a little vague as he was elderly but he said they made these for their frontline working dogs.
I googled such and am still researching but to yet no avail.

My question would be has anyone seen or know of these or similar, any information would be greatly appreciated.