Mitsubishi Electric PLC Compatible Battery, MELSEC-F Series Battery for Memory Backup, Application: FX3G / FX3GC / FX3U / FX3UC / FX5U / FX5UC, Applicable Series: For memory backup, Note: Memory backup battery for FX5U, FX5UC, FX3G, FX3U, FX3GC or FX3UC. Expected lifespan of 5 years. Can also be used as a backup battery for IU2-3M10 or IU2-1EMES of MELQIC (data collection analyzer).