Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Extra Power

For anyone using AF lenses with Image Stabilization this accessory to your Canon camera is a must. It really extends the time you can use the camera without need of changing the battery. This is great for field work taking nature pics. I would recommend an extra set of batteries though, charged and ready to use, just in case. If you're like me you can get lost behind the lens and spend hours trying for the right shot and you might run out of power, I have. Get one, its worth the price!