What IS important for someone to know, is under what conditions the device will
be used. There are long range, short range. Pet alley, and pet immune. There
are Passive infrared and microwave and combinations of both. There are indoor
and out door. There are curtain and and ceiling mounted. 360 degree 180 degree
and 90 degree and that's not getting into the various adjustments that each of
the manufacturers provide. All of which will be considered by an installer,
depending upon where you want to use them and what you want to protect and
detect. The other very important item is where to mount the unit in your
building. There are certain things you should avoid, depending upon