Stereo Mini to 1/4
Details of connections:
MP3 player to Bose System
Plug this into your MP3 Player (headphone or line out jack) (black end to MP3 Player)
and attach coloured ends to this:
Pointy end then plugs into channel 3 or 4
You could get two RCA to 1/4" adapters, but then you would have to use both channels 3 & 4. Since the {{L1}} is mono, there is no particular reason to use two channels.
Click the images to see the ordering information if you want to get them from Radio Shack.
(disclaimer: I have nothing to do with Radio Shack but they have decent pictures).