The Pico--DS3231 is a expansion module for Pico. It incorporates high precision chip DS3231 and uses I2C bus for communication. More external sensors are allowed to be connected thanks to the stackable design. Standard for Pico header, supports for Pico series Onboard high precision 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 Colour:blue Material:plastic Package Contents: 1 * Pico for Raspberry Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.