Württemberg, Leutkirch, Oberzeil, Postablage. Clear oval postmark on 3kr carmine on bluish entire, additional "Leutkirch, 4/6, 73" cds alongside indicia; light edge wear and tone spots, F.-V.F., a very rare contract Post Office marking with only three examples reported. Estimate  $750 - 1,000. $0 (Image)