These are some common tools used to work on this device. You might not need every tool for every procedure.
The link below brings you to our troubleshooting page, where you can find common issues and ways to repair them.
Background and Identification
The feature-packed and waterproof Polar M400 offers a wide variety of features for runners. Some of these features include a GPS watch, which keeps track of pace; a Fitness Tracker, monitoring a range of daily activities (such as calories burned to sleep quality); and a H7 Heart Rate Sensor, finding your target heart rate zone. The available colors for the M400 are either black or white.
The main component of the M400 is the screen. To ensure the M400 remains in place, it features a rubber strap that can be fastened with a security loop. On the front of the M400 there are five buttons: two on the left of the screen and three on the right. On the left side, the backlight is activated by the top button, and bottom button is the "scroll back" and "end button" for setting the watch. With the three buttons on the right, the top button is for scrolling up, the middle is to select and start activities, and the bottom right is for scrolling down. On the back of the M400 is the micro-USB port, which is protected by a rubber flap. The company name, Polar, and the model, M400, are located above and below the screen on the front side.