1963 underpaid cover sent air mail to Cape Town, South Africa, with a pair of 5NP on 1d, a 10NP on 1½d and a 20NP on 3d, all tied by MUSCAT 7 OC 63 cancels. A ‘T 4c’ tax mark has been applied and a pair of 2c postage dues affixed and cancelled Cape Town. A fine and scarce cover.