An EQ pedal uses several linear filters that allow the user to boost or cut specific frequencies. Often, a EQ pedal is used as a boost for guitar solos or to eliminate feedback. In other instances, though, EQ may be used to modify a guitar or bass signal in a more drastic fashion. Some amplifiers, such as the Mesa/Boogie Mark series or Carvin X-100 B, contain a built-in EQ to help the guitarists shape their sound more precisely. Common EQ pedals offer different bands depending on the size of the pedal, but it's not uncommon to have five, six, or as many as ten bands of EQ available for modification. Everyone from Slash to Lyle Workman have used EQ pedals at some point.