The tool was rated 4.2 on Google Play. There are in-app purchases and advertisements in this application. The statistics demonstrate that the app is popular mostly among Samsung and Sony users.
A free .apk installation package of Call Blocker Free 5.2.38.00 is available from Droid Informer and you can have a look at users' reviews on this site. Prepare 2 MB of free space on your device for this app installer and keep in mind that it requires Android 4.1 and above.
As users state, the app possesses such a benefit as a great interface. As users see it, the obvious drawbacks of this application are huge ads and annoying notifications.