The LED indicator (pictured below) located on the right side of the headset, signal the different modes your headset is in per the descriptions below:
Red (Continuous) - Indicates battery charging
White (Continuous) - Indicates battery fully charged and connected to a USB power source
Blue (Blinking) - Indicates pairing mode, waiting to pair
White (Blinking) - Indicates waiting to connect
White (10 Second Interval) - Indicates headphones are connected and switched on
No light display - Indicates Headphones are off or in normal operation