Textbook M31 canteen marked ESB 41

Excellent textbook early war M31 (Feldflasche) canteen with aluminium flask in light used condition. The flask and the felt cover are both nicely marked ESB 41 which indicates production by Eduard Sommerfeld, Berlin in 1941. In textbook configuration with an excellent black bakelite cup marked gfc 1941. Excellent matching canteen in good slightly used condition!