You get a real mobile number that can be called from normal phone lines (some limitation can apply due to local telecom operators).
VoipOneClick does use RSA certificate 2048 bit, AES 128 chiper and TLS/SRTP protocols to encrypt the communication, that is a light encryption still valid against hackers. (For military grade encryption 8192 bits, search "Kryptotel" in this store.
It allows an high voice quality without delay even when it is used on mobile networks
VoipOneClick works on every wifi/mobile 3g/satellite network and everywhere there is an internet connection.
The application is ready to be used just after the download without any configuration or registration of personal data.