Dear Brian; Actually, it may not be that simple. My 900 MHz iBook comes with both; a square white box with fold-out two prong, or a removable extension you can add in line that is 2-prong. Checking the power rating is your best bet, unless they are both 60 watt. If so, they are interchangeable. My iBook is 60, but some are 45 (mostly older ones with lesser drives, I would guess.) Sorry I cannot tell you definitively. Going to Apple's online technical support, It looks like they are the same: "Important: Compatible with PowerBook G4 (Aluminum or Titanium models) or dual-USB iBook (500Mhz Power PC G3 or higher). " http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore?productLearnMore =M8943LL/A I got there after finding your Powerbook, reading tech specs under support, and then this is the link to its power supply. In other words, one has the 3 prong extension on, the other is the base 2-prong. I think. Valerie On 12/11/04 2:28 PM, "Brian Olesky" <brian4 at sbcglobal.net> wrote: > Don't have the answer yet, but this should be simple. If someone out there > has a 600 Mhz iBook, or a new 15" AlBook, could you please tell me which > Book you have and whether your power cord extension has a 2- or 3- prong > connection to the wall switch? I looked at the Apple specs and they both > take different power supplies, so I do need to find out which is which.