Complex sentence: In 2004, Hi-n-Dry released the Mark Sandman box set "Sandbox", which contained two CDs and a DVD of previously unreleased material spanning Sandman's musical career.
Split into simpler sentences: In 2004, Hi-n-Dry released the Mark Sandman box set "Sandbox". It contains two CDs and a DVD of previously unreleased material spanning Sandman's musical career.