By Devan Coggan
February 09, 2016 at 01:44 PM EST
Phil Bourne/Redferns via Getty Images

The full lineup for this year’s Eaux Claires Music & Arts Festival hasn’t been announced yet, but organizers Justin Vernon (Bon Iver) and Aaron Dessner (The National) recently mailed out cassettes including rarities and B-sides from artists who are set to perform to festivalgoers who bought early tickets.

One of those tracks is a never-before-heard B-side from Bon Iver, titled “Haven, Mass,” probably recorded between For Emma, Forever Ago and the band’s self-titled album. Vernon confirmed the track was Bon Iver song tweeted that it’s a “very old song” from 2009 or 2010.

The Eaux Claires festival runs Aug. 12 through 13 in Wisconsin. Listen to “Haven, Mass” below.