The sisters released their second studio album, the Christmas-themed "Acoustic Hearts of Winter," on September 26, 2006.
Njun album je ponovno izšel v avgustu 2006 s tremi novimi pesmimi, vključno z uspešnico "Chemicals React" ter dvema novima verzijama pesmi "Collapsed" in "Something More"; drugo izdajo je doživel tudi v Veliki Britaniji.