This is a Eisernes Kreuz / Iron Cross first class (EK1) by maker Rudolf Souval from Vienna.
While the cross is not visibly maker marked it can easily be attributed to maker Rudolf Souval from Vienna because of the shape of the silver frame. Especially the die flaw on the upper left corner of the upper arm is easily visibla, but there are other characteristics too.
This is a wartime made cross and not one of the many postwar Souval crosses.
Very cool is the extra plate under the catch, to create more grip to keep it in place, it is a wartime repair and is done very well.
Simply a great Ek1 cross!