This is what you get when you mess with them: Radiohead are making a trove of recently leaked session audio officially available.

Last week, 18 hours of takes and tracks from the sessions to the band’s 1997 landmark OK Computer (expanded and reissued with bonus material in 2017) leaked. Among the contents were alternate takes, mixes and live material, including versions of beloved tracks “Karma Police,” “No Surprises,” “Airbag” and “Exit Music (For a Film)” as well as lesser-known fan favorites like “Lift” and “True Love Waits.” (This extremely comprehensive document breaks down the exhaustive amount of material.)

Today, Radiohead guitarist Jonny Greenwood explained how the leak came to be on the band’s social channels. “We got hacked last week – someone stole Thom [Yorke]’s minidisk archive from around the time of OK Computer, and reportedly demanded $150,000 on threat of releasing it,” Greenwood wrote in a statement.

But the band have turned the potential negative into a positive, putting the entire archive up for purchase on Bandcamp for the next 18 days. All it costs is £18 (about $23 American), and all proceeds will go to Extinction Rebellion, a nonviolent climate activist organization. Thus, fans can explore the material (“Never intended for public consumption,” Greenwood writes, “though some clips did reach the cassette in the OK Computer reissue”) at low cost, with said cost going to a worthy cause. Each tape is unlabeled, with the shortest running about 18 minutes and the longest almost 71 minutes long. Make sure you have that document handy to parse through it all!

Again, you can purchase the archive here.