“Jailbreak” by Thin Lizzy and “Folsom Prison Blues” by Johnny Cash are two of the best jail-themed songs ever written. But how do actual prisoners consume and listen to music? Illegally downloading MP3’s isn’t an option when you’re behind bars, and this New York Times article has discovered that jailbirds across the country are still buying music—on cassette.

Yes, the lowly audio cassette is still gasping a last puff of air in jails across the country, and a California company called Pack Central is earning a nice little sum of money from it. Cassettes cover about 60% of Pack Central’s sales to jails, and their yearly earnings are usually in excess of $1 million. Current best selling songs in the slammer include Lil Wayne’s Tha Carter III, Al Green’s Greatest Hits, and Linkin Park’s Hybrid Theory.