Use APKPure App
Get Lock old version APK for Android
Ultra-simple lock screen
It is an ultra small app for locking screen. No ads in it!
Note:
1.If you want to uninstall, first deactivate the procedures in "Settings -> Security -> Device Manager", then uninstall it.
2.The app is currently not suitable for use with "Fingerprint Unlock".
3.This application uses the administrator's privilege of the terminal