The Ernie Ball Music Man John Petrucci JP15-7 celebrates 15 years of John Petrucci signature models. Separating it from the JP13 is its okoume body and roasted flame maple neck, which features 24 medium-jumbo stainless frets (that promise to hold up better than standard frets). The JP15 is also outfitted with two DiMarzio Illuminator humbucking pickups and Schaller M6-IND locking tuner promising better tuning stability.