The Third Reich Heer(army) and Luftwaffe(airforce) rank of Obergefreiter is equivalent to that of Corporal in the current day US Army and US Airforce. The modern British army equivalent would be Lance-corporal. The Kriegsmarine equivalent of Obergefreiter was called Matrosenobergefreiter whereas the Waffen-SS equivalent was the SS-Rottenführer.
The rank markings of an Obergefreiter was a chevron as well as two stripes.
For a more complete overview
of which ranks existed
, see Wehrmacht ranks
The page that helped me with this writeup is no longer on the internet, but it used to live at www.wehrmacht-association.com/Open_Pages/ranks.htm