The caller application is the best free number detector (number book) specifically directed to users in Saudi Arabia.
When you receive a phone call from an unknown person, you can search for his number using the Saudi numberbook, and you can view this information about the number:
1- Caller name - if available
2- The number is in local form
3- The number is in international format
4- Fraud rate
5- Number status (used for marketing calls or not)
6- Line type (landline or mobile phone)