G-Sensor: DVR will save videos as undeletable files when gravity acceleration any accident happens. SOS function: Under recording mode press Down button momentarily to activate SOS function the current video will be saved as undeletable file.Silent Video Recording : Under recording mode short press up button momentarily to off microphone the microphone icon on screen will change to No voice icon. Do not worry about your secret talk. Image Rotation Function: When the camera need to be mounted upside down turn on the Image Rotationthe video footages and pictures will be upright.