The MB-N10 Battery Grip extends off-grid operating time by a factor of 1.8 (approximately) and provides a more comfortable balance when using long telephoto lenses. The battery grip accepts up to two Nikon EN-EL15b lithium-ion batteries (sold separately). Protected against dust and moisture ingress, the battery grip features an LED charge indicator for each of the two battery compartments. Batteries can be replaced during operation. This is especially convenient for longer video or interval shooting. The batteries can be charged directly in the battery grip using the EH-7P AC power adapter (sold separately). When the battery grip is attached to the camera, the camera must be turned off in order to charge the batteries via the grip',s built-in USB port.