yes I see it also on mine I just got it from Amazon I think it said it lets you just know the device is in use the solid on light is a power on one and it turns on as soon as you plug it in your pc with no driver installed then after its set up driver and all but you are not mining the bottom one will not flash till you start mining since that's like a warning not to remove it from the pc you must stop the mining program and make sure the light stops flashing to know its safe to unplug it hope this helps you out dude since I know that no documentation comes shipped with the device