Ah, the ’70s — paisley silk shirts, feathered hair, and driving your brother’s AMC Pacer to the roller rink with Bachman-Turner Overdrive’s Greatest Hits squealing inside the 8-track player.

It’s a snapshot of a few short years in American history, when the reigning portable album format was 8-tracks — those clunky, easily damaged plastic relics marketed to music fans after the LP and before the cassette tape. Or so you’d think.

As it turns out, while scrolling through my phone last night, I all of a sudden saw something that caused an immediate double-take: a picture of Purple Rain, by Prince… on 8-track tape.

Didn’t Purple Rain come out in 1984, I thought? What the hell was going on here? Something about it seemed so incongruous that I had to call its owner, noted 8-track collector Steve Ciaffa, to get an explanation.

“Eight-tracks were basically put out to pasture by the major record labels by 1982,” Ciaffa tells me. “But then record club 8-tracks continued for another five years after that — basically, in Rolling Stone or wherever, you’d get the Columbia House or RCA record club thing: ‘7 LPs for a Penny!’ What most people didn’t realize was you could order 8-tracks from them too. So they’d do these small-batch 8-tracks for people who wanted them.”

In other words, while your sister was busy ordering Madonna and Duran Duran cassettes for her Walkman, if you were stuck with an 8-track player (in a hand-me-down station wagon, most likely), you could order Purple Rain on 8-track tape from the RCA record club.

Ciaffa found his copy for 50 cents in the 1990s, when he’d spend his days off going to thrift stores looking for 8-tracks. But Purple Rain actually fetches between $35–$65 online these days, thanks to a niche-but-robust collector’s market. Ciaffa estimates that out of the 22 million copies of the album sold worldwide, only around 5,000 copies were made on 8-track — and even then, most of those ended up in landfills, or broken and strewn across the road.

It’s worth wondering, with such a low number produced: Did Prince know? “I think it’s pretty unlikely that he was even aware that it was available on 8-track,” Ciaffa says. “What’s even more incongruous is that actually, this was not the latest Prince 8-track that was released. Sign ‘o’ the Times, from 1987, also came out on 8-track.”

In 1988, after Fleetwood Mac’s Greatest Hits served as a renewal of vows between era and format, but also the final title to roll off the assembly line, the record clubs finally stopped making 8-tracks altogether. Sign ‘o’ the times, indeed.

Read more about Steve Ciaffa and his 8-track obsession here.