Nikon MB-D10 Multi Power Battery Pack for Nikon D300 & D700 Digi
[049607591253]

what i like about this grip is that you can use it WITHOUT any batteries inside the grip's chamber as long as you have batteries inside your d300/d700 body....the grip is fully functional. because of this, i always have the grip attached and only put the batteries in the grip for extra juice to shoot 8fps.