the D300 uses en-el3, which is the same as d200 and D70....
it comes with a charger to charge the en-el3 batteries....
but the battery pack can be used with AA batteries or the en-el4a battery.
AA batteries and charger, not a problem cause almost everyone has one.
but if want to use the en-el4a battery, you must buy charger yourself, and not cheap.
unless user already have a D2x or D3 camera, then no problem...
so, in short, want to use vertical grip for D300, got to shell out quite a bit of money due to charger....
cause i think the weight of the vertical grip and AA batteries is quite a lot compared to en-el4a alone.... moreover, dun know what is the battery life of AA battery on the D300....