Postage due is a term used for mail sent with insufficient postage. Postage Due stamp is a stamp added to an underpaid piece of mail to indicate the extra postage due.
Malayan Postal Union issued a set Postage Due stamps from1936-38. It features the value in Numerals.
Malayan Union- Federated Malay States (FMS) was a Federation of four protected states in the Malay Peninsula -Selangor, Perak, Negeri Sembilan & Pahang- established by the British Government in 1895and which lasted till 1946, when together with two former strait settlements (Malacca & Penang) and the unfederatedMalay states they formed the Malayan Union.