In 1961, shortly after Karsten had moved to Arizona from California, Karsten came out with Ping 69 FTL (flat, thin, long) putter.  This fine example has its original 35 1/2" shaft and Golf Pride Informer grip. The inside of the back cavity is marked with Ping's Scottsdale address. 

When Karsten moved to Pardise Valley, a suburb of Phoenix in 1960, he set up a Post Office box in Scottsdale in order to differentiate his business address from another putter maker operating in Phoenix—John Reuter, Jr., the maker of the Bulls-Eye line.  Karsten marked all of his clubs with the Scottsdale address so anybody who saw another golfer using a PING putter would know where to write to place an order. In late 1966, Karsten moved from his garage to a small commercial building in Phoenix.