Sony SRF-39FP has a transparent case, designed to thwart contraband concealment. The radio often appears on the commissary lists of U.S. federal prisons, hence the "FP" suffix
https://en.wikipedia.org/wiki/SRF-39
Sony D-FJ003FP, Sony WM-FX193FP, SONY SRF-M35FP
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Sony SRF-39FP has a transparent case, designed to thwart contraband concealment. The radio often appears on the commissary lists of U.S. federal prisons, hence the "FP" suffix https://en.wikipedia.org/wiki/SRF-39 Sony D-FJ003FP, Sony WM-FX193FP, SONY SRF-M35FP