The Pico-RTC-DS3231 is a RTC expansion module specialized for Raspberry Pi Pico. It incorporates high precision RTC chip DS3231 and uses I2C bus for communication. More external sensors are allowed to be connected thanks to the stackable design.

Standard Raspberry Pi Pico header, supports Raspberry Pi Pico series
Onboard high precision RTC chip DS3231, with backup battery holder
Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
Optional format : 24-hour OR 12-hour with an AM/PM indicator
2x programable alarm clock


Operating voltage: 3.3V
Backup battery voltage:2.3V ~ 5.5V
Operating temperature:-40°C ~ +85°C
Power consumption:100nA (sustains data and clock information)


Package Includes:
1 X Precision RTC Module for Raspberry Pi Pico

Wiki page: https://www.waveshare.com/wiki/Pico-RTC-DS3231