Rubber (types I and II) and metal (types III and IV) handstamp overprints made in Rudnik nad Sanem in 1944 on General Gouvernement stamps. Rudnik is a small town in southeast Poland, east of Tarnobrzeg.
There are four types of Rudnik nad Sanem overprints:
Type I: "Poczta", "Polska", "w Rudniku" (three lines, 25 x 17 mm) and a bar cancelling the German text.
Type II: "Poczta Polska", "Rudnik", "nad Sanem" (three lines, 25 x 18 mm) and a bar cancelling the German text.
Type III: "Poczta Polska" in an arc above a stylysed eagle, "RUDNIK", "n/Sanem"
Type IV: "Polska" in the upper left corner and "RUDNIK n SANEM" and a bar cancelling the German text centered at the bottom of the stamp.
Stamp Domain Poland page about the postal history of Rudnik nad Sanem 1944, written by Jan Kosniowski