30 Kopek registered postal stationery envelope with a black overprint "Pleskau 20 kop", with additional postage Pleskau Mi. No. 10-11 x, overpaid, with advertising slogan, cancelled with the stamp "PCKOB * K * 24.12.41", oblique crease, examined by E. Keiler, photographic finding Robert Brunel VP (2025).