This module is without battery(battery type is LIR2032) because we received the notice from the post office that they don\'t accecpt goods with batteries.Thereforeplease buy cautiously. This is the DS1307 Real Time Clock developed by one of our designer waiman. The module comes fully assembled and pre-programmed with the current time (ok so it\'s our current time - MST). The DS1307 is accessed via the I2C protocol. Two wire I2C interface Hour : Minutes : Seconds AM/PM Day Month Date - Year Size: 28x25x10mm Leap year compensation Accurate calendar up to year 2100 1Hz output pin 56 Bytes of Non-volatile memory available to user Package include: 1x DS1307 Module