Stopwatch Board Clock Professional Digital Chess Clock 1. Multifunctional: countdown, plus seconds, multi segment timing, time limit, positive timing, delay function, and mute. 2. Battery power supply: The rear of the product is equipped with a dry battery installation port, as well as a power supply port. You can connect devices such as a power charger and a charging bank through a USB cable to power the product. You need to connect the power supply to use it, and you cannot store electricity. 3. Widely used: suitable for multi clock chess games, such as Chinese chess, chess, go, etc. 4. Easy to use: During the competition, the parameters of both sides can be modified, and different basic time and auxiliary parameters can be set on the left and right sides. 5. Big rocker key: The rocker timing key allows the person who is cocked to count, providing a , quick response, and convenient control, making it more suitable for fast chess. Type:Chess Clocks Model Number:Chess Digital Timer Two power supply methods: DC 3V power supply (two or four batteries can be used)(Not included batteries) USB power supply (connected to the power supply, unable to store power). Colour:Black Material:ABS Size:197x126x58mm Package Contents: 1 x Chess Digital Timer 1 x USB Cabl Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.