4d blue on creamy white GV postal stationery registered envelope of South Africa (H&G C1) used with added 1913 ½d blue green and 2½d bright blue 'GV Head' issue of South Africa (SG 3b & 7) tied by fine strike of MARIENTAL 'German' type cds dated 18.1.1921 with boxed straight line 'MARIENTAL' registration marking alongside. Addressed to WINDHOEK with arrival cds on reverse. Fine & scarce.