In the box, you get the grip and 2 battery trays.
The first holds up to 2 NB-2LH batteries. It will function normally with just a single battery and batteries need not start with the same charge. We went 6 days and 1000 pictures on a pair of aftermarket NB-2LH clones last year at the Oshkosh airshow. Certainly nothing to complain about.
The 2nd tray holds 6 AA batteries should the need arise - it hasn't for us. We'll try and do an endurance test ourselves, but we've heard you don't get much shooting time off the AA's.
