It's a USB device. It looks like a bulky thumb drive with an
I button inside. They are programmed by Motorola with x number of refreshes. Every time you refresh a radio (firmware update), the count drops down by one. You also need the .cvn file. I believe the last one released was R20.50.10. I know I downloaded R20.50.09. I don't think I ever got the very last one and you can no longer download them. I spoke to M last week and was told all they will provide is the .cvn file that will firmware update an XTS/XTL2500. Any other Astro series radio, the file they send you will not have the corresponding .cvn file. You need the previous release .cvn file(s) that contain firmware updates for ALL Astro series radios.