In 2013, Boards Of Canada set tails wagging when a small number of mysterious records credited to the pair appeared in record shops across the world without any warning on Record Store Day. Now, one of those records is being listed on Discogs for resale.

As The Vinyl Factory reports, the first known copy of the record was discovered at Other Music in New York City and was later sold on eBay for $5,700. A second copy was then found in London at Rough Trade East. Other Music, the store at which the first copy was discovered, is now listing a mint copy of Boards Of Canada’s —— / —— / —— / XXXXXX / —— / —— for $4,500 here.

Only three copies are known to be in existence so far. As the store explains, “Other Music was given two copies of this mystery record on Record Store Day in 2013, one to give away and one to keep. Here’s the second copy… unplayed in perfect condition.”

The mystery in 2013 formed the first part of the cryptic campaign devised by Boards Of Canada and Warp Records to promote the duo’s fourth album Tomorrow’s Harvest which was their first in eight years.