This is a German Army surplus tricot quarter zip shirt in brown. This shirt is part of the base layer issued by the Bundeswehr to keep their troops warm. They look great worn on their own as well.
What is tricot, you ask? It is a special way to weave cotton that makes it very smooth on one side, which makes it a great choice for comfortable base layer clothing.
These shirts are used in very good condition. They'll just show typical signs of minor use and should be free of any rips or holes.