E R Seal, Image by StuE, Found by Saxonman
Found near Tolleshunt Major, Essex, 20mm.
Both sides have a circular border of pellets, one possibly with a crown at the top and ER in the centre, the other probably with a quadrafoil at the top and O in the centre.
The O suggests it is a flour bag seal, flour used to be categorised into '00', '0', '1' and '2' grades, '00' being the finest and whitest and working down to the almost wholemeal grade '2' flour.