Product Features:

Timing accuracy (in a plus or minus): ± 5ppm (± 0.432 sec / day)
Power supply voltage: +2.3V to +5.5V 
±3℃ accuracy digital temperature sensor 
To provide continuous battery backup
Temperature range: -40 ℃ to +85 ℃ 
Low-power consumption
Device package and function compatible with the DS3231
Complete clock calendar functions which include seconds, minutes, hours, date, month and year, provide valid until the year 2100 leap year compensation
Two calendar alarm
1Hz and 32.768kHz output
Reset button debounced input and output
High-speed (400kHz) I2C serial bus

100% brand new and high quality.
DS3231 Precision RTC Clock Memory Module for Arduino Raspberry Pi
High timing accuracy, ± 5ppm (± 0.432 sec / day)
±3℃ accuracy digital temperature sensor 
Device package and function compatible with the DS3231
Complete clock calendar functions and provide valid until the year 2100 leap year compensation
Two calendar alarm
Modules can adapt itself 3.3V and 5V systems without level conversion, super convenience.


Package included:

2  x  DS3231 Real Time Clock Module
Technical support is NOT included in this auction