What's included:
DSTE BL-3 Battery Chamber Cover x 1
Required when battery is teamed with MB-40 or MB-D10 battery pack;

Compatible with the following Battery Modle:
For Nikon EN-EL4A Battery

Compatible with  Camera Model: 
For Nikon D-SLR D900/D700/D300/D300S Camera and MB-D10 Battery Grip 

If there is any questions, just contact us, we will alway be here for you.