why not make it transparent?

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