LANMU 2PCS DS3231 AT24C32 IIC Module Precision Real Time Clock Quare Memory for Arduino Size: 38mm (length) * 22mm (W) * 14mm (height).Weight: 10g Operating voltage :3.3 - 5 .5 V Clock chip: high-precision clock chip DS3231 Clock Accuracy :0-40 range, the accuracy 2ppm, the error was about 1 minute Calendar alarm clock with two