Specification:
■  Battery: CR2032 (update on October 25th)
■  Size: 38mm (length) x 22mm (Width) x 14mm (height)
■  Weight: 8g
■  Operating voltage: 3.3 - 5.5V
Clock chip: High-precision clock chip DS3231
Clock Accuracy: 0-40 °C range, the accuracy 2ppm, the error was about 1 minute
Calendar alarm clock with two
Programmable square-wave output
Real time clock generator seconds, minutes, hours, day, date, month and year timing and provide valid until the year 2100 leap year compensation
Chip temperature sensor comes with an accuracy of ± 3 °C
Memory chips: AT24C32 (storage capacity 32K)
IIC bus interface, the maximum transmission speed of 400KHz (working voltage of 5V)
Can be cascaded with other IIC device, 24C32 addresses can be shorted A0/A1/A2 modify default address is 0x57
Packing: single anti-static packaging

Wiring instructions (with Arduino uno r3 for example):
SCL → A5
SDA → A4
VCC → 5V
GND → GND

Package included:

1 x DS3231 AT24C32 IIC module