Features:AT89C2051-based of four electronic clock kitKit Model: YSZ-4Supply voltage: 3V-6VPCB Size: 52mm * wide 42mmFunction:1. Seconds correction (for precise School)2. Switch to every minute independent display interface3. whole point of time (8-20 o&39;clock chime can be turned off)4. Two alarm settings (you can turn off the alarm function)Kit Features:A. 0.56 inch special red digital clock for display;B. Import AT89C2051 for master chip;C.1.2mm thick PCB made from military grade FR-4 board;D. accurate travel time, travel time error range error -1 to +1 seconds every 24 hours.Package included:100% Brand New1x Electronic Clock DIY Kits1x ManualNOTE:This produce is DIY kits, not the end product We don&39;t provide technical assistance please make sure you are familiar with the product before purchasing.