This is an exhibition cover posted from the Post Office Philatelic Exhibition (Pameran Setem Pejabat Post) in 1966. The exhibition ran for a period of 19 days from 17 August - 4 September!! Wau, that was pretty long. It could be the exhibition held for the longest period in Malaysia history.
The cover has a very nice design featuring the 1965 Malaysia birds series. What are odd about it is the stamps affixed on it. Those are Singapore stamp commerating the the 1st anniversary of republic issued on 9 August 1966. As mentioned in my previous blog, Singapore had merged with Melaya, Sabah and Sarawak to form "Malaysia" as the result of 1962 Merger Referendum of Singapore. Singapore was expelled from the federation two years later, on 9 August 1965 after heated ideological conflict between the state's PAP government and the federal Kuala Lumpur government.
So if Singapore was expelled from Malaysia in 1965, was its stamps still valid to be used for postal purposed within Malaysia? Ironically, the cover was also cancelled on 31 August 1966, Malaysia national day. Classic.