Speek offers simple User Interface and super audio quality VoIP calls in affordable rates. Speek works on all iOS devices and supports calling over WIFI/EDGE/3G/LTE.In order to use these app, end users need to login using their mobile number. Key features include: 1. Lowest battery usage with highest reliability / stability on App store. 2. Lowest latency. 3. Exceptional voice quality. 4. Bandwidth normalization. 5. Voice/Video packet negotiation 6. Bluetooth support. 7. Excellent audio quality, even on older devices. 8.Supports calling over WIFI/EDGE/3G/LTE. 9. SIP stack fully compliant to RFC. 10. Background / multitasking support. 11. Speakerphone, mute and hold.