Seven-string guitar 2nd Law" album tour. Dino Cazares uses custom seven-string Ibanez guitars; Christian Olde Wolbers has his own signature Jackson seven-string guitar, Jeff Loomis has a signature model made by Schecter and Stephen Carpenter has several of his own models released by ESP. In the early 2000s, Roger McGuinn (renowned for his skills on the twelve-string guitar and for his long association with The Byrds) worked with C. F. Martin & Company to develop a seven-string folk guitar. McGuinn's guitar (currently being marketed by Martin) is tuned the same as a standard folk guitar with steel strings, but the third (G)
Guitar frets, which are metal strips (usually nickel alloy or stainless steel) embedded along the fretboard and located at exact points that divide the scale length in accordance with a specific mathematical formula. The exceptions include fretless bass guitars and very rare fretless guitars. Pressing a string against a fret determines the strings' vibrating length and therefore its resultant pitch. The pitch of each consecutive fret is defined at a half-step interval on the chromatic scale. Standard classical guitars have 19 frets and electric guitars between 21 and 24 frets, although guitars have been made with as many as 27 frets.