Vai helped design his signature Ibanez JEM guitar series. Seems that guitar players all over the world agree that it is the ultimate rock guitar, blending the best features of historical favorites with visionary advancements. Vai also has a 7-string model designed by him named Ibanez Universe. He also has a signature Ibanez acoustic, the Euphoria. Before Ibanez, he briefly endorsed Jackson guitars, but this relationship only lasted two years. His two main guitars are white JEMs dubbed "Evo" and "Flo", each with their own unique modifications.
He has a custom-made triple-neck guitar that has the same basic features as his JEM7V guitars. The top neck is a 12-string guitar, the middle is a six-string, and the bottom is a six-string fretless guitar. The JEM & Universe guitars have proven themselves to be incredibly exciting and important rock guitars over the past 10 years. They are guitars that rewrote the rules and changed guitar history. Inspiring a number of JEM-dedicated websites and a fiercely loyal and supportive following, the Jems spawned dozens and perhaps hundreds of imitators.