I want to point out that you should never buy a generic battery, like the person from San Diego who reviewed the S410 on May 15, 2004, was recommending. Yes you'd save money, but there have been many reports of generic batteries exploding when charged for too long. And don't think if your generic battery explodes you can sue somebody and win millions. These batteries are made in sweatshops in China, India and Korea, and I doubt you can find anybody to sue. So play it safe, both for your own sake and the camera's sake. If you want a spare, get a real Canon one.