Another design by Vai was the Ibanez Universe, the first production seven-string guitar, which was released in 1989. The Universe incorporated many of the aspects that made the JEM a unique instrument (2 octave fretboard, full floating tremolo, humbucker/single coil/humbucker pickup configuration, angled output jack and deeper body cutaways), with an added low 'B' string, allowing for new low-range sonic possibilities. Used by Vai on much of "Passion and Warfare" and all of Whitesnake's "Slip of the Tongue", the Universe was a large stepping stone for the burgeoning Nu-metal genre (with bands such as Korn, Limp Bizkit, Fear Factory and Meshuggah having adopted the instrument and incorporating it into their signature sound).