This MagSafe Battery itself is more expensive than a lot of new entry Android phone. The description of this external battery saying it provides all day battery for Air with +65%. So 165% is the true amount of battery need for true all day? I guess all day could mean these:
Without the thick bricky external battery: 24 hours sleep mode without touching the phone
With the external battery: you can turn on the phone sometimes but don’t play game
Without the thick bricky external battery: 24 hours sleep mode without touching the phone
With the external battery: you can turn on the phone sometimes but don’t play game