NO BATTERY NEEDED: Wind-up mechanism ensures that you'll never have to interrupt a game to replace a batteryProfessional mechanical analog Chess Clock.INCREDIBLY ACCURATE: The timing is accurate, and the daily error is no more than 1 second.SO SIMPLE TO USE: Just wind it up and set the hands becompatible withe . The tilted base makes it easier to view the clock dials during Recommend: Available compatible with Chess,Chinese Chess, and I-GO.colour: as shownMaterial: PlasticSize: 15x5.5x9cmPackage Contents:1 x Chess TimerOnly the above package content, other products are not included.Note: Light 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.