|Rickenbacker Electro-Spanish Ken Roberts Model|
|Period||(1931-1936 production) Official Release 1935|
|Body type||Hollow, Semi-hollow|
|Neck joint||Set neck|
|Scale||25" First Full Scale Electric in History|
|Body||Mahogany (with binding)|
|Neck||Usually Mahogany or Maple(with binding)|
Vib-Rola patented by Clayton Doc Kauffman
Manufactured by Rickenbacker, the Electro-Spanish Ken Roberts is considered the pioneering "grandfather" to the modern electric guitar as it was the first commercially produced full, twenty-five inch scale electric guitar ever made.  Produced between 1931-1936, the instrument line was officially released in 1935 and was terminated in 1937. It is estimated that less than 50 total quantity were produced & sold between 1931-1937.  It was the first model of its kind to offer players an extended neck that joined the body at the 17th fret, enabling extended playability on the 22 fret neck; a design element that persists in the current day electric guitar. Another key element found on the Electro-Spanish Ken Roberts, was the stock equipped hand operated "Vib-rola" vibrato device produced by patent holder Clayton Doc Kauffman.
The Electro-Spanish Ken Roberts was revolutionary for its time and several of its design elements were cutting edge and exclusive to the model, setting precedence for future electric guitars development into the 1940s and 1950s.  Prior to the Ken Roberts release, lap-steel electrified instruments were played by placing the instrument on the lap of the player. The Electro-Spanish Ken Roberts was designed to play standing up, vertical, with a strap as practiced in modern electric guitar performance. Historians attribute the Electro-Spanish Ken Roberts cutting edge design elements to its unfortunate negative acceptance by the public, ultimately leading to its commercial termination.
Both the "Electro-Spanish Ken Roberts" and "Electro-Spanish Model B" set the stage for solid body guitars to develop; including the notable Fender Stratocaster and Les Paul whose electric solid-body would reach mainstream notoriety in 1952, produced by Gibson Guitar Corporation.