Part Number: Pico-RTC-DS3231 Precision RTC Module for Raspberry Pi Pico, onboard DS3231 chip 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