mm43
The 12 year life for the battery is the same for the portable RESCU 406 ELT that Honeywell makes, which is also fitted to some B787 aircraft.
My guess would be the same type of battery, but l am not in a position to check at this time.
The batteries are replaced however at 10 years as per the MPD for the fixed ELT.
It is the same interval also for the portable ELT, which aligns with the second 5 year off wing inspections.