Karina of K-pop girl group aespa promotes the CD player version of its upcoming album, "Armageddon." Captured from Instagram

CD players lost their ground in the 2000s following the advent of the MP3 format, but they have recently returned to the limelight thanks to K-pop girl group aespa.

The quartet, which will put out its first full-length album, "Armageddon" on Monday, announced Friday that the album will also be made available in CD player version. This rendition comes with a working CD player, wired earbuds, photo cards as well as graphic stickers, and is priced at 145,000 won — approximately seven times more expensive than ordinary albums.

Nonetheless, the CD player albums are already sold out on many platforms, including SM TOWN&STORE, an official online store run by aespa's management company SM Entertainment. The exact number of preorders is unknown, but hundreds of thousands of people are known to have put the albums on their wishlists. They will be released on July 19.

"It seems more than 1 million CD player albums will be sold," a fan commented on the online community, theqoo. "I think SM should produce more to cater to demand."

Another wrote, "I am not a follower of aespa, but I still made a preorder to get a good CD player."

The CD player album of K-pop girl group aespa's "Armageddon" / Courtesy of SM Entertainment

The rationale behind their popularity is simple: People believe that these retro-infused CD players are not only worth owning, but also useful. Most of them cannot listen to the music of their favorite stars through CDs included in K-pop albums as they do not have CD players in this streaming era. But now, they can do so if they snap up aespa's new album.

Industry insiders note that these albums suggest a new approach for the K-pop world where many fans throw away physical albums and CDs after collecting photo cards and getting receipts, which can be exchanged for "coupons" for fan signing events.

With these albums, SM Entertainment also tried to "capture the quintessence of music."

"Our CD player albums have materialized the intangible value of music, enabling listeners to own and appreciate it," the company explained.

Aespa, consisting of Karina, Winter, Giselle and Ningning, debuted in 2020 with the track "Black Mamba." Its upcoming album will be fronted by the two lead singles: "Supernova" and "Armageddon." Prior to its official release, the group unveiled "Supernova" on May 13, which is reigning atop major streaming charts in Korea and abroad. According to SM, "Armageddon" is a hip-hop dance track emphasizing the message, "Only I can define myself."