this is not German it looks to be a Spanish helmet.
Spanish M42/79 I believe
Spanish Modelo Z
The Spanish M1942 origianly had a 3 finger liner making it the Modelo Z. In the 70's a new liner was adapted to the M1942 creating the model M1942/79 as is the case in the helmet pictured in this thread.
Here is a link that exlains it better, with photos:
Military Collection of Peter Suciu
Hope this helps.