Usage Tips:This digital clock is perfect for chess and other games that require countdown, count up, bonus, and delay times. It&39;s lightweight and small in size, so it fits in most bags conveniently and is portable to take to and from club or tournament events.Features:Large flexible button with better sense of press. of ABS plastic durable material shell.Available for bonus &delay mode.Portable energy saving design.Functions:Basic: Set basic time.BonusSet basic time and bonus time.DelaySet basic time, second reading times and time.Positive Timing: Set basic time to be 0 for overall rationing systemSpecifications:Material: ABSColor: Black / Yellow(Optional)Battery: 2 * AAA battery (Not included)Screen size: 103 * 23mm / 4.06 * 0.91inItem size: 140 * 88 * 45mm / 5.51 * 3.46 * 1.77inItem weight: 105g / 3.70ouncePackage size: 150 * 100 * 50mm / 5.91 * 3.94 * 1.97inPackage weight: 157g / 5.54ouncePacking List:1 * Chess Clock