GB NATO FELDPOST REGISTERED STATIONERY 1961 WILDING UPRATED 1/6 + 2d

QE2 pre-paid 1/6 postal stationery Forces Overseas Registered Letter uprated with 2d Wilding; to British Consulate General in Dusseldorf; Field Post Office 993 cancels + Registered etiquette; N.A.T.O Feldpost Registered form signed on the back.