Manufactured by Ro-Pat-In Corporation, Rickenbacker, the Electro-Spanish Ken Roberts is considered the pioneering "grandfather" to the modern electric guitar as it was the first commercially produced, full-scale (twenty-five inch) electric guitar ever produced. It was the first artist signature model having been named after Ken Roberts, a friend of (Ro-Pat-In President) George Beauchamp. In addition, the instrument was the first electric guitar to provide a stock appointed tremolo arm; designed & patented by Doc Kauffman. The Electro-Spanish Ken Roberts holds the current world record for the highest price paid for a guitar, after selling in 2017 for $7.5 million.