Whistle.
This application is completely secure to download. Naritasoft is the creator of the app that is related to the Tools category. Google Play shows that Whistle is rated 3.7 by its users.
The developer released a new version of the app on Oct 7, 2020 and over 100K users downloaded and set up this application. There are advertisements in Whistle. A number of users set up this application on their HTC and Samsung devices.
Get the installation package of Whistle 2.2 that is free and take a look at users' reviews on Droid Informer. The app is designed for Android 5.0 and higher.
As users state, the app features such a disadvantage as too many ads.