If you are looking for a decent quality headphone, try to get the headphone that works with Pansonic SV-AS10 Camera/MP3 Player. You don't need a seperate adapter to use this Headphones. coz they have slim jack that fits right into Treo 650 Jack. If you wanna order it, call Panasonic and give them this above SV-AS10 model and ask them to send you HEadphone for it. I checked and the operator told me it cost around 18.20 plus s.h. according to him, the model number for that headphone is L0BAB0000173 (all zero's), but please double check with the camera model. GOOD Luck. by the way Panasonic Parts phone number is 1-800-211-7262,