Dag för Dag is a Swedish-American brother and sister duo based in Stockholm. The band's core members are Sarah and Jacob Snavely. Formed in 2007, they are supported both on stage and in the studio by a drummer. Their first tour was with friends Shout Out Louds in January 2008 and since then they have supported The Kills, Wolf Parade, Lykke Li, Handsome Furs, Wintersleep and Cursive. The band's name, Dag för Dag, is Swedish for "day by day".
https://en.wikipedia.org/wiki/Dag_f%C3%B6r_Dag