Covered under Edwin McClain’s December 1928 US patent, this Hagen sand wedge has a dramatically curved face, top to bottom, and a large, broad sole.  Bobby Jones even used one of these in the 1930 British Open.  In 1931 the USGA adopted a new regulation that made any club with a concave face non-conforming.  Consequently, Hagen stopped producing this concave sand wedge.

This example has its original 34 1/2" shaft and leather wrap grip.  This historic and highly unusual club is in outstanding condition.   

For more about the Hagen concave sand iron, see TCA2 Vol. 1 p. 283-284