Details of the later pattern Mercedes D.III valvetrain, using the relocated rocker box design, with rotary shafts to operate the fully-exposed <a href="https://en.wikipedia.org/wiki/roller_rocker" class="extiw" title="w:roller rocker">w:roller rocker</a> arms.
Unknown, artist's signature not entirely legible in scan of image.
British Flight Magazine, June 20, 1918 issue, page 683