This AC Adapter Kit provides AC power to the camera.
Canon ACK-DC40 - power adapter is rated 4.0 out of 5 by 1.
Rated 4 out of 5 by Nicholas Name from Works as designed with my Canon PowerShot S120I purchased this power adapter, hoping to increase the amount of time I could use the power-hungry Full HD 60fps video mode of my Canon PowerShot S120 camera. On battery, the 'low battery' warning appears quickly. Using this AC adapter, I can now record about 15 minutes of continuous video at a time, a significant improvement over relying on battery power. I understand that the S120 was not designed as a video camera, so I accept the limitation.