Nickel silver based and in a very good, slightly worn condition with a typical patina.
Not marked but a known variation that has been attributed to the company of C.E. Juncker, Berlin. See Philippe de Bock, The German Panzer Assault Badge, p.41 - 45, type 1.1.1.
Probably the most desirable and mother of all Panzer Assault Badges.
C.E. Juncker NS PAB in silver (Porsche Type)