Features: 【High-Precisions Clock】: The DS3231 integrates a temperature-compensated with accuracy up to ±2 minutes per year (within the ranges of 0°C to +40°C), ensuring precise time recording. 【Battery-Holder】: The module is for button battery (battery package optional) for maintains continuous operating even during main power outages, preserving accurate time and date. 【Dual Voltages Compatibility】: Supports both 3.3V and 5V power supplies, facilitating connection and use with various microcontrollers offering high flexibility. 【I2C Interface】: Utilizes the I2C communication protocols, which is simple and easy to use. Data transmission requires only two wires, simplifying wiring and programming complexity. 【Multiple Functions】: Beyond basicly time and date functions, it supports extended features like alarms and scheduled wake-up, catering to diverse application needs. Specifications: Component: PCB Size: 13.4x13.4mm/0.53x0.53in Package : With Battery/ Without Battery Quantity：1/3/5pcs Usage scenarios: Widely used in smart home controllers, data loggers, electronic calendars, temperature and humidity monitors Package Includes: 1/3/5pcs DS3231 real-time clock module note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.