OLEA TANKSCHIFFAHRTS GMBH.

The flag is blue with a centred black cross edged in white, thin black lines running through the white edging. At the centre is a white circular area containing a black O. Rosanoski’s correction to the published description specifies that the white circle has no defining outline: a narrow black ring lies within it around the O, whose strokes are thinner at the top and bottom.

The funnel source appears to show the white circle outlined in black around the O. Rosanoski thinks the line more likely represents a ring within the circle, as on the flag.