Mechanical Structure: The mechanical structure with the timing button is adjusted to make the timing operation intuitive, convenient and .For chess games: No battery required, this clock is powered by clockwork and easy to . It is similar to the operating mode of a quartz watch.High : the daily tolerance is no more than 1 second, suitable for different chess games.High Quality Material: This chess clock is made of plastic, strong and durable, not easy to be broken. exquisite workmanship.Easy to Maintain: The chess clock should put up the contact with materials and exposure to sunlight, rain, drops and not in the place near strong magnetic fields.:Timer button operation :press left button to timer of left watch and timer of right watch, vice .press right button right to stop time measurement left to time at the time Button less than half (. both sides of the button are in the horizontal position),The 2 watches are in the stop state.size:15x5.5x9cmMaterial:plasticcolour:bluePackage Contents:1 * Chess TimerOnly the above package content, other products are not included.Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.