Key features include:
1. Lowest battery usage with highest reliability / stability on app store
2. Lowest latency of all iOS softphones.
3. Exceptional voice quality.
4. Bandwidth normalization.
5. Voice/Video packet negotiation
6. Bluetooth support.
7. Excellent audio quality
8. Supports calling over WIFI/EDGE/3G/LTE.
9. Background / multitasking support.
10. Integration with the native iphone contact list.
11. Speakerphone mute and hold.