Most of the attention in gadget design goes to the latest and greatest high-tech toys for first-world consumers - but that's not the only customer who can benefit from thoughtful design. The audio player of choice in prisons isn't cloud-based, streaming, MP3, or even CDs: it's the simple Sony SRF-39FP AM/FM radio. It features a clear housing so it won't be broken open to check for contraband; it eschews anything fancy, like digital reception, to conserve power and deliver more listening time for the prisoner's battery purchase. And of course, as a radio it comes with a built-in range of never-ending free content. The right design choices for the situation are what makes it, as the New Yorker's Joshua Hunt writes, The iPod of Prison.