Universal CO, Propane and Natural Gas detector

["djenka2" <marakana97500@xxxxxxxxx>]

Hi,
I bought Kidde 3 in 1 detector (CO, Propane and Natural Gas) but it's
not what I was looking for.  In the Kidde guide it says that human will
smell the gas before the detector gets activated which I don't like at
all, hmm what the point of having one then.  It will activate the alarm
at 25% level where 30% is needed for explosion.  I know there were some
universal 3-in-1 detectors that activates alarm at 5% but don't know
the brand anymore.  The Kidde is loud but when the basement door is
closed I can hardly hear the alarm on main floor, not to mention one
floor up where all the bedrooms are.
Is there anything on the market (and what brand) that will do at least
CO and natural gas and that can be interconnected to one more unit (on
the main floor or first floor) that is not wirelles.  I've heard there
are some units that can be interconnected thru 110V receptacles where
they are plugged in.  If not, I don't mind even running wires.

Thanks