MB-D10 is an ergonomically designed grip for extended stability and potential for vertical shooting, for use with the Nikon D300 and the D700.
The MB-D10 grip is supplied with a cradle for an additional EN-EL3e and 8x AA batteries. Combined with the grip both options will give extended shooting time and easier handling when taking portraits.
But to obtain 8fps when using the D300 you have to get the one of the following combinations:
Nikon MB-D10 Grip + BL-3 battery chamber cover + EN-EL4a battery**.
Nikon MB-D10 + 8x AA batteries
The solution to this is to purchase the first bundle listed below and save money at the same time!
** If you do not already own a Nikon EN-EL4/ EN-EL4a battery then you will need to purchase either the Nikon MH-21 or MH-22 chargers