בידספיריט | British WWI military mail in

British WWI military mail in Egypt: 20 JU 1918 stampless OHMS stationary cv ex General Staff Intelligence Section GM 2 (CAIRO) to ALEXANDRIA, tied by unlisted 2-line skeleton DS (if Proud-D5 then on 1st day of use - but FPO lettering here spaced differently) + FB unlisted GSIS red oval cachet w/dater; b/s same day BAPO Z (ALEX.) & next day ALEX.-E arr.; filing-hole at back, slit open for display.