Just replaced the batteries in six of mine. If you have the anti-theft caps installed you will need a very small phillips screw driver. Take out the three screws and remove the cap. Then use the install tool to hold the sensor and unscrew the cover with your fingers. The battery slides out. Install a new battery paying attention to the polarity and reassemble using a new Oring. I elected not to reinstall the anti-theft covers and just reinstalled on the valve stems. I have since requested and received some new sensor to stem seals. I need to replace a couple of them, maybe later this week.