German, Flour Bag Seal, Stettin, RM 2 Seal, Image & Found by Popsandme.
Found in W. Yorks, 18.5mm x 12mm.
A continuous raised circle contains on one side RM with 2 beneath and on the other side St over W.M
R.M. - Roggenmehl - Rye flour.
See p.15, Meelloodjes, een ‘verborgen’ geschiedenis, B. D. Poppen, "From the former German city of Stettin several seals are known, both of the Dampfmühle and of the Walzmühle. The Walzmühle was founded in 1838, located directly on the Oder, over which the grain was brought in by barges."