The 'iPod of Prison': What makes this Sony radio an instant classic behind bars?

The SRF-39FP isn't the most sophisticated piece of kit, but thanks to some unique attributes its a favourite of American prisoners

Sony's SRF-39F. Image courtesy of Museum.

It’s been a long time since Sony has held much sway in the market for portable audio players, but there’s one demographic with whom the Japanese company is still incredibly popular: American prisoners.

This is all thanks to an AM/FM radio built especially for the market. Known in typically utilitarian Sony-speak as the SRF-39FP (the FP stands for ‘Federal Prison’) the radio was first released fifteen years ago but remains a firm favourite to this day.

This is according to Joshua Hunt, author of an article for The New Yorker that outlines the enduring appeal of the so-called “iPod of prison”.

As with most gadgets, the appeal lies in the specs: the radio’s clear plastic build means that inmates can’t use it to smuggle contraband around the prison; it’s reportedly near-indestructible; it runs for forty hours from a single AA battery (a big plus given the limited budget of prisoners) and its also exceptionally powerful.

The receiver is so strong that Hunt reports the story of one enthusiast who used the device to pick up signals from Japan, a distance of just under 7000 miles – perfect for getting good reception behind those thick, prison walls.

Of course, for a prisoner a radio is about more than just entertainment – it provides a lifeline to the outside world whilst also offering a rare chance for privacy in a life that is being constantly watched. For more info on this fascinating bit of tech trivia, check out Hunt's original article.