The iPhone Duo’s battery capacity is now official: 4,883mAh — split across two cells, per Apple’s EU energy label published ahead of its global launch. That figure lands between the Galaxy Z Fold 8 Ultra’s 5,000mAh (per GSMArena) and the standard Z Fold 8’s 4,660mAh (per Android Authority). It’s also larger than the iPhone 18 Pro Max’s battery, though Apple hasn’t disclosed that figure publicly, and no source here compares them directly beyond endurance ratings for the outer screen. The EU label adds two key durability metrics: a rated battery endurance of 51 hours and 30 minutes per full charge cycle, and retention of at least 80% capacity after 1,000 full charge cycles under default settings. That’s fewer cycles than the Z Fold 8’s 1,200-cycle rating, but Apple’s figure reflects real-world usage patterns baked into iOS. Not lab-only conditions. Pre-orders opened last week. Deliveries begin later this week. The device is eSIM-only worldwide, so the 4,883mAh spec applies uniformly, no regional variants. Samsung hasn’t confirmed a ‘Z Fold 8 Ultra’ model in any official channel. GSMArena’s note that ‘Z Fold 8 Ultra is 5000mAh, not 4800’ appears to reference an unannounced or leaked variant. Not a launched product. Android Authority only cites the standard Z Fold 8’s 4,660mAh battery and 1,200-cycle rating. No pricing or regional launch dates appear in either source. Neither outlet reports charging speed, wireless specs, or thermal behavior, just the raw capacity and cycle data from the EU filing. The iPhone Duo goes on sale globally this week.