C51 4 Bits Electronic Clock Electronic Production Suite DIY Kits Description: AT89C2051-based of four electronic clock kit Supply voltage: 3V ~ 6V PCB Size: 52 x 42mm Function: Seconds correction (for precise School) Switch to every minute independent display interface whole point of time (8-20 o'clock chime can be turned off) Two alarm settings (you can turn off the alarm function) Feature: 0.56 inch special red digital clock for display Import AT89C2051 for master chip 1.2mm thick PCB made from military grade FR-4 board Accurate travel time, travel time error range error -1 to +1 seconds every 24 hours Package included: 1 x Electronic Clock DIY Kits 1 x Manual Note: This produce is DIY kits, not the end product! We don't provide technical assistance please make sure you are familiar with the product before purchasing. Apologize in advance.