Spalding waterfall backspin irons were produced primarily in 1920 and 1921 under a patent issued in 1919 to William F. Reach. They were designed to add backspin to the golfers shots, be it a traditional strike or a cut sot.

This example is stamped "Spalding Kro-Flite" etc. On the back of the blade.  A large name in the center is believed to be that of Joe Seka.  This example is marked "Pat Applied For," so you know it's an earlier model.

Nice original shaft. Original grip shows some wear. Head has a nice, untouched, dark patina.