smart tire module

[Torcano]

I am the second owner of a 2009 DB9 and just noticed a small module under the dash which appears to be remote tire pressure/temperature monitor.
Are these units battery powered or hot wired? How do they work? It looks likes the only thing it can do is light up if there is a tire problem. See attached picture.
Thanks
T

[Torcano]

Thanks. Is the unit always on when the car is running or do I have to hit a power button? It looks like there is a power button to the left of the 4 led lights.

[Torcano]

BTW, I assume this was an after market device installed by previous owner and not something that was standard on the '09 DB(.

[Torcano]

Thank you all very much. You have been very helpful. Most cars costing half as much have tire pressure readings available on the information displays that can be called up at will. Despite this, none are as nice looking as the DB9 in my opinion. I am guessing the DB11 will be so equipped.
RK