They have a pretty harsh legal warning on their website - looks like they might hunt you down for some jail time if you tried to put your own Walkman in one of the pockets...
"Since we have filed for U.S. and international patents on our adaptation of the Technology Enabled Clothing™ System and related technology, any attempt to copy or replicate any of the unique features of our adaptation of the Technology Enabled Clothing™ system, including, without limitation, any use of the lining or other areas to accommodate wires for a device not included with the garment, will be considered an infringement of our intellectual property rights and will be acted upon in accordance with all applicable laws."
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