Ultra Battery Saver implements more comprehensive management of the battery in your phone, effectively extending the life of your battery and the practical using time of your phone. And today I would like to share the tip that how to use the ultra battery saver in Redmi 9t.
1. Click the Settings on the phone.
2. Find the Battery&performance in the list.
3. Click it and you will see the notice of the ultra battery saver, then choose ok.
4. In a second the ultra battery saver will start.
5. If you want to turn off the ultra battery saver, just click the top right corner here.
6. And the ultra battery saver will turn off automatically.
I will be super happy if this tip could help you.
Mike Lee-111 
Tech Elucidations 
Iman iman 
Jane Brown