The 2.4 ounces player is capable of playing MP3/WMA formats and AAC in the future. With 128MB built-in flash memory, the company claims you can fit 4 hours of digital music encoded at 64kbps via WMA. Sadly, at this high compression ratio, we could hear hiccups and occasional dropouts. Music encoded at 128kbps is a closer match to CD-quality, but it also reduces the playback time to about 2 hours. With Rio 800’s collapsible earphones, we didn’t notice any substantial improvement on sound quality when playing files with 160kps or higher bit-rate. During our tests, playback lasted for 6 to 8 hours before a 2-hour recharge is required.