The Canon BP-110 Battery Pack is compatible with Vixia HF R20, R21, and R200 high-definition camcorders. (It's also compatible with Canon Legria models HF R26, R28, and R206.) The BP-110 ships with those camcorders, so this is a replacement or additional camcorder battery.
The lithium-ion BP-110 is rated to power the camcorder for up to 85 minutes while it's recording in LP mode. It's an intelligent battery system, which means it communicates its charge level to the camera so that it can be displayed in the LCD screen.