VERY RARE KOWEIT REGISTRATION MARK; c.Oct. 1917 unfranked env. (small faults) to England endorsed 'On Field Service' signed at lower in the same hand and with framed "R/KOWEIT" (type 5) h.s. on front. The rear with two indistinct cds and an oval "REGISTERED/LONDON" d.s. Exceptionally rare registration mark. Cross Reference: MILITARY - WWI, REGISTERED MAIL, INCOMING OVERSEAS MAIL (Image)