From Manufacturer
This B&H kit consists of two Watson Pro Buddy System High-Load V-Mount Batteries and a Watson Pro Dual Position Li-Ion Battery Charger. This kit has been assembled to provide you with two high-capacity batteries that can be carried on a plane, and a two-bay charger. Each battery splits in half for airline travel and supports a 15A draw when recombined. Each battery supports 15-amp maximum load, which allows it to support cinema cameras rigged with accessories, large LED lights, or other gear that uses a V-Mount.
The reverse SMBUS communication is enabled through the V-Mount connection and enables RED ONE and DSMC cameras to display detailed battery info in the viewfinder. The charger supports charging two 6.6Ah batteries simultaneously and larger capacity batteries sequentially. Additionally, when the charger is plugged into a power supply you can use it as a camera power supply and a charger at the same time.