What is Apple Watch Low Power Mode? Which models get battery-saving feature?

Apple has announced a significant update for Apple Watch models, with a new Low Power Mode enabling users to squeeze up to 36-hours of battery life from multiple smartwatch models.
Announced during the Far Out event, The feature means the traditionally-stingy 18-hour battery life can now be boosted in much the same way life can be elongated on an iPhone and iPad.
With Low Power Mode engaged, activity tracking and fall detection will still be available, but some more power-hungry features like the always-on display will be sacrificed. It won’t automatically check whether you’re working out either. However, that’ll be a worthwhile trade-off for many users Apple Watch users who’re annoyed by the need to replenish their smartwatch every single day.
The ability to stretch battery life to 36-hours is also massive bonus for Apple Watch users who may be camping or travelling and unable to charge for a period of time.
Which Apple Watch models get low power mode?
While the feature was revealed during the Apple Watch 8 section of Apple’s Far Out event, it’s software-based and will be available on all models from the Apple Watch Series 4 onwards when running the new watchOS 9. That’ll include the new Apple Watch SE models and its predecessor. Sorry, Apple Watch 3 users and below, but you’re out.
Previously, Apple has only offered a Power Reserve mode on previous Apple Watch models, which enabled you to still see the time when battery life gets below 10%.
“Power Reserve lets you see the time on your Apple Watch while preserving your battery life,” Apple explained. “While your Apple Watch is in Power Reserve, press the side button to show the current time. In Power Reserve, your Apple Watch and iPhone won’t communicate, and you can’t access other watch features.”
This is a huge improvement on the Power Reserve feature and a big update for existing Apple Watch users, as well as those picking up the new Apple Watch Series 8 and Apple Watch SE 2. The Apple Watch Ultra meanwhile, will benefit from 60 hours of battery life in some modes.