So what does it do? The main advantage with this device is it can be left in an area that your investigating, a walkway for example, anything that passes within the devices preset distance will make the lights emit and it will make a buzzing sound due to the temperature change. A switch under neath the unit allows you to select five positions from 1 inch to 5 inch, the closer something gets the more lights emit and with of course a warning buzzer.
The unit has an extendable aerial and it's this that makes the connection of the change in temperature and warns you that something has crossed it's path.
The device also has a automatic baseline so your able to place the unit wherever you wish and after a few seconds it will stop buzzing and baseline the temperature.