There is many alarm apps. There is many bad alarm apps. This one is small and simply works:

- Alarm siren when your smartphone charger is unplugged
- Can't be deactivated without unlocking your phone
- Alert notification that indicates alarm is active
- Can't be silenced with volume buttons
- Simple and clean user interface
- No advertisements
- No thieves
- No theft
- No bs

Keep in mind this is beta software. It works great on my phone. I hope it does so on your phone. If it doesn't, send me an email to [email protected], state your brand, model and Android version and I will look for the rest.