Metalcore combines elements of hardcore punk with heavy metal, thrash metal or extreme metal. Generally, metalcore guitarists use harmonized guitar riffs and solos, drummers use hardcore d-beats and double bass drums, and vocalists use a sing-along style. A distinguishing characteristic is the “breakdown“, whereby the song is slowed to half-time and the guitarists play open strings to achieve the lowest-pitched sound. Metalcore generally differs from thrash metal in that it avoids the “chugging” guitar sound and focuses more on melody than aggression. Prominent metalcore bands include Bullet For My Valentine, Killswitch Engage, All That Remains, and Shadows Fall. Most modern metalcore bands are from North America.