"The gravikord is an electric double harp invented and patented by Robert Grawi in 1986. It is modeled after the 21 string West African kora. It is made of welded stainless steel tubing, with 24 nylon strings but no resonating gourd or skin. The bridge is a synthetic material designed very differently from the kora and the range of pitches is greater. While the hands are in a more ergonomic and natural position to the strings, the playing technique is similar to that of the kora: the player plucks the strings with the thumb and index finger of each hand."
Quoted from Top Ten Bizarre Musical Intruments http://listverse.com/music/top-10-bizarre-musical-instruments/