1. No battery required, clockwork, easy to use, similar to quartz movement 2. Divided into left and right movements, each full spring can last at least 36 hours, and the daily error in running accuracy is about 3 minutes 3. Material: plastic case, zinc alloy movement 4. Maintenance: The chess clock should be protected from contact with corrosive substances, avoid exposure to sunlight, rain, falling and close to strong magnetic fields 5. Size: about 15x5.5x9cm 6. Weight: about 280 grams Instructions: 1. Place the chess clock on a flat table before use 2. Press the direction indicated by the arrow on the back to fully wind up the spring. When the spring is wound up, do not turn it hard to avoid damage. 3. Set the hand: first set the minute hand to the 12th position, or set the minute hand to any specified position as needed. When turning the hand, be sure to turn the watch in a vertical position to avoid the minute hand getting stuck on the indicator flag and causing the minute hand to shift. 4. Start: Press the left button, the left watch stops and the right watch starts to start, press the right button, the right watch stops and the left watch starts to start (but it is not advisable to press the button hard to avoid damage) 5. Speed adjustment: If there is a speed error, you should use a small metal rod to adjust the speed mechanism in the hole in the direction pointing left and right of the moon-shaped hole in the back cover