Unlike most Android handset makers, Apple doesn't disclose precise details about the iPhone's battery or RAM.
But thanks to Chinese tech regulator the Ministry of Industry and Information Technology, the gaps in Apple's specs for the iPhone XS, iPhone XS Max, and iPhone XR have now been filled.
These details are likely to come out after iFixit does its customary teardown of Apple's phones, but MacRumors has found links to Apple's descriptions on the ministry's website.
The 5.8-inch screen iPhone XS features a 2,658mAh battery and 4GB of RAM. That's a 2.2 percent smaller battery than the iPhone X's 2,716mAh cell, but it's 1GB more RAM than the iPhone X's 3GB of RAM.
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Despite the lower capacity battery Apple says the iPhone XS lasts up to 30 minutes longer than the iPhone X.
With a larger 6.5-inch screen, the iPhone XS Max unsurprisingly has a larger capacity battery of 3,174mAh, which is the largest battery any iPhone has had. It also features 4GB of RAM. Apple says the iPhone XS Max has a 1.5 hour longer battery life than the iPhone X.
The more affordable iPhone XR with its 6.1-inch LCD or 'Liquid Retina' screen also has a bigger battery than the iPhone X at 2,942mAh.
Apple says the iPhone XR is the longest-lasting iPhone currently available. Like the iPhone X, the iPhone XR has 3GB of RAM.
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iPhone XS review CNET
A slight notch above the iPhone X.