בידספיריט | British WWI military mail in

British WWI military mail in Egypt: 19 NO 1918 stampless OAS civilian stationary cv. ex APO SZ 24 (SUEZ) to CAIRO tied by Proud unlisted single dateline pmk - similar to D3 but wider legend spacing; endorsed by officer & passed censor; b/s next day CAIRO-E arr.; slit open for display & re-closed at top.