It's not a problem if people don't mind (I don't mind if I can afford $3499) to buy multiple batteries, thanks to it's external.

I was just pointing out the fact that they said "This needs to sit on your face for 8 hours or more." when it is limited by the fact that it will only be available for the 2 first hours.

The battery is for on the go usage. It also has a charger for “all day use” when you are stationary.