The M43 Service Field Cap (Einheitsfeldmutze) was the standard issue German overseas cap from 1943 to the end of the war. The major change from the old M35 cap was that it had a bill to shade the eyes and face. On the side of the cap, there were flaps of fabric which hooked into the front cap insignia and could be put down to protect the ears from cold which came with acknowledgement from the troops on the Eastern Front.
It differs from the Bergmutze by being made from uniform cloth and having one large button instead of two smaller buttons. Also, the Wehrmacht "eagle" patch was a trapezoid instead of a T-shape.
The former M35 Field Cap
The SS Cap
The Heer Field Cap