Postcard Panzer soldiers fieldpost Luftwaffe Felddivision 21

Postcard showing a photo of a German Panzer soldiers. Used as Luftwaffe field post Apr.43 by a Gefreiter of (field post number L53815) Panzerjäger-Abteilung Luftwaffen-Feld-Division 21 active in Staraja-Russa (Russia) at that time, to a Gefreiter of (field post number L04075) 2. Batterie leichte Flak-Abteilung 751 based in Bruck (Austria or Eastern Prussia?).