Australian WW 1 Identity Disc 1907 pattern, thicker aluminium disc with 1908 Australian Coat of Arms on one side. The other side is engraved with ‘wiggle work’ to read:
This type of disc is referred to on on this page on the Australian War Memorial Site. They are recorded as being similar (but thicker) to aluminium 1907 standard ID discs with 1908 Coat of Arms on the reverse. The AWM suggests they are old government discs or perhaps railway locker tags.
John Stewart Graham (view service record here) enlisted in 1916, served in the 22nd Battalion from late 1916 to the end of the war and was wounded in action once and gassed once.