Part No: CP1W-BAT01
 
Battery set for N/NA-type CP1E CPU Units
Mount a Battery to an N/NA-type CPU Unit if the data in the following areas must be backed up for power interruptions
DM Area (D) (except backed up words in the DM Area), Holding Area (H), Counter Completion Flags (C), Counter Present Values (C), Auxiliary area (A), and Clock Function 
Omron CP1E CPU and Accessories
The E-type Basic CPU Units provide cost performance and easy application with only basic functionality.