My Treo 650 was only usable for minutes at a time away from an AC plug before I replaced my battery with this product. Absolutely seems to work as advertised. Perhaps not fair of me but I deducted one star for the fact that the battery won't last a full day with "decent" mixed use -- phone calls, internet usage, mp3 playing. Add use of bluetooth to that list and you're certain to still need an AC charger at some point during the day.But it can go all day long if I cut out one of those activities.