Description [Compatibility]: The RTC clock module can be adapted to 3.3 V and 5 V system without level conversion [Compatibility]: The RTC clock module can be adapted to 3.3 V and 5 V system without level conversion [Compatibility]: The RTC clock module can be adapted to 3.3 V and 5 V system without level conversion [Accuracy of 3 Digital Temperature Sensor]: Within -40 C to +85 C temperature range, timing accuracy is maintained at 5ppm ( 0.432 sec / day), easy and convenient to use [RTC Clock Module]: Complete clock calendar functions include seconds, minutes, hours, day, date, month and year timing, provide valid until the year 2100 leap year compensation Specifications: Temperature range: - 40~85 color: as show Weight: 2g Package included: 4 x RTC Clock Module( battery are included)