Sum 41 is a Canadian rock band from Ajax, Ontario. Originally called Kaspir, the band was formed in 1996 and currently consists of lead vocalist, guitarist and keyboardist Deryck Whibley, guitarist and backing vocalist Dave Baksh, guitarist, keyboardist and backing vocalist Tom Thacker, bassist and backing vocalist Jason "Cone" McCaslin, and drummer Frank Zummo. In 1999, Sum 41 signed an international record deal with Island Records and released its first EP, Half Hour of Power, in 2000. The band released its debut album, All Killer No Filler, in 2001. The album achieved mainstream success with its first single, "Fat Lip", which reached number one on the Billboard Modern Rock Tracks chart and remains the band's most successful single to date.
