The Phone supports two GSM SIM at a time. If there is a call on one SIM then second SIM will be inactive during the call and vice versa. The key USP of K777 is a Mega 2.8 inch Bright Screen, 1.3 MP Camera & Powerful Speakers with Crystal Clear Sound. K777 is also loaded with a Fascinating Proximity Sensor, Multi format Video Recording & Playback, Wirefree FM Radio with Recording & Expandable Memory upto 8 GB.