Ok guys, I've measured the plug and it comes out to 3.0mm (outer) x ~1.5mm or so (hard to tell).
That doesn't look like it falls into any of the standard sizes that shadesbass' wikipedia link shows. Also, I found the following page (which only further confuses things):
http://www.pdainternalbattery.com/pd...rchargers.html
The first (AC) charger (Part # SW10-S050-10) listed shows PMP-120 compatibility with the plug measurements of 4.0mm x 1.5mm x 11.0mm.
The second (AC) charger (Part # M2-10US05-A) is for the PMC-120 and shows plug measurements of 3.0mm x 1.5mm x 11.0mm.
Which would backup iRiver's claim that the PMP-120 charger wouldn't work for the PMC-120.
NOW, here's where the confusion is...
The first Car Charger listed (Part # ICJ-300) shows the same measurements as the PMP-120 AC Adapter (SW10-S050-10). BUT...the second Car Charger (ICJ-100) shows the same measurements as the AC adapter for the PMC-120 (M2-10US05-A) and lists compatibility for the PMP-120...
Would someone who owns the Car Charger for the PMP-120 measure the outer dimension of their charger plug for me and confirm this?