The 2 RBS (rigsbankskilling) stamp was the second Danish stamp issued 1 May 1851. The stamp was printed in blue on paper with watermark 1 (crown) using the denomination as the design. Like the 4 RBS stamp, it was first produced by the Ferslev printing house and later, in August 1852, by the Thiele printing house. The RBS stamp is Denmark’s most valuable stamp with a catalog value of $1,500 – $3,000 for a cancelled copy and $10,000 – $25,000 for a mint mint (postfresh) copy. Today’s stamp is a unique cancelled block of four. In 2004 a mint block of four was sold for more than $300,000.