Prussian, Customs Seal, Ohlau, Steuer-Kontr Seal, Image by StuE, Found by Barney Rubble.
Found in the Essex/Suffolk/Hertfordshire area, 17mm, 10.1g.
Eagle displayed facing right, sword in right talon globus cruciger in left // 1516, K. PR. STEUER-KONTR around
From Paul James (Flags Forum) - Prussian coat of arms, the letters "K.PR." would stand for Königreich Preußen (Kingdom of Prussia) and Steuer-Kontr[ollen] is something like "Tax Control"
From John Kristensen (Danzigman), "New found info - Plomba Podatkowa Pruska XIX wiek, translated from Polish it says - Seal Tax nineteenth century Prussian."