Telephone call Timer

Zenith timer from way back in the days of timed telephone calls,says on it pat.42336/o8 then S.G.D.g.373533 then D.R.P. 489464. under the hand it has an cross then35608 the word ZENITH and next C of A P.M.G. 34.
and Swiss made. on the back it has No 1079124 then Swiss made again. A Commonwealth of Australia, Post Master General item.
Where it came from I've no idea it was in a box of stuff I was looking through, the brown ring seems to be Bakelite and the rest nickle plated brass, Looking at google where a few of these are shown the lever should have a Bakelite cover on it, the lever still moves and the hand goes around but it then returns to it's original position. sorry about the quality of the photos after quite a few attempts these were the best.