This is a nice relic exmaple of a German M40 single decal helmet. This one has its original rubber band camoflauge still intact on it and the rubber is in good conditon and hasn't yet dried out. The decal is still there though the rust has taken a bit of it away and there is more underneath the rubber band.
There is traces of grey paint all around the helmet as well. This helmet was found in the Gorodishche district of Stalingrad in 2019.