The following megaphone is a recent addition to my collection, and although not badge related it is worth sharing.
I have traced the use of megaphones by the NZ Military as far back as early 1907, my one sadly is not dated but I would date it between 1910 to the 1930s, it has a small arrow mark stamped in the leather, and hand written in very faded black Indian ink are the words “Auckland Machine Gun Section.”
