This putter head is made from Pyralin, a type of vulcanized rubber, and was originally patented in the US by Willie Dunn Jr. in 1903. Dunn assigned his patent to the "Kempshall Mfg Co, Arlington, NJ," and that information is stamped on the top of the clubhead. Kempshall was an early American club and ball maker.
Three circular lead weights in the back of the head still have their original pyratone covering in place. The 33 1/2" shaft and sheepskin grip are original. An excellent example of this elusive collectible!