Gottlieb's Flipper [Model 175] © 1960 Gottlieb.
Model Number : 175
Released in October 1960. 1,100 units were produced.
Gottlieb's Flipper was the first 'add-a-ball' machine and introduced the concept of extended play.
Concept by : Alvin Gottlieb
Design by : Wayne Neyens
Art by : Roy Parker
Collector's Guide to Vintage Coin Machines - Richard M. Bueschel - Page 106