This is a Super Capacitor Real-Time Clock module, it design for Raspberry Pi, but it also can be used to Arduino.
Plugging it into Raspberry Pi GPIO interface, and all is ok. This is the easiest way to keep it in time.
Compared with the Mini RTC Module,it not include battery. Because it has super capacitor.
Features:
Super capacitor
• Smaller
• Work in 3.3V and 5V
• Supported Raspberry Pi and Arduino
Specification:
DS3231 RTC IC
• Self-adjust 3.3V and 5V
• Size: 14x16x12 mm