South Africa Postage Due 1927 2d Offset of Frame Block

POSTAGE DUES: 1927-28 2d black & (deep) mauve, variety OFFSET OF FRAME (SG D19var). VF/UM lower two rows of the pane, sheet margins on three sides, a BLOCK OF TWELVE, the offset of frame particularly vibrant. Unusual, a striking Postage Due variety, fantastic in large multiple thus.