Otto Hackbarth began advertising his forked hosel putters in 1910, taking order by mail.  Hackbarth wanted a center-shafted putter, but to help prevent the putter from twisting when putts were struck off center, he devised a forked hosel that would attach at both the heel and toe. 

Chick Evens, the winner of the US Open and US Amateur in 1916, made it famous.  Evans used this club during a good portion of his career, and with great success before this club was declared non-conforming by the USGA. 

The head shows some use, and the two arms are solid, not cracked like they sometimes are. The sole itself is marked "Otto Hackbarth / Pat 687539." Lead is inlaid down the center of the sole.

33 3/8" original shaft. Wrapped leather grip. Condition as shown. This putter is the top left club in the group image