The S-21 is the last of the 70th anniversary flaps. The two previous styles were almost completely sold and there was a need to order another loom of the 70th anniversary flap to provide flaps for the post camp ordeal. This order was made from a different company and the patch size was larger than the previous flap. The difference in size is measured from top to bottom. Therefore this is considered a different patch. See the other two 70th anniversary flaps.