There will be no remote temperature in the top half and there will be no bars on the receive indicator to the left of the display. But first make sure that the system will connect by having the remote sensor and display unit unit close together. You may have to pull the batteries out of the display unit and force it to search for the remote sensor. In my case, the fringe area was about 36 feet through an exterior wall. This would result in the display unit losing connection with the remote sensor sporadically. I moved it closer by about 10 feet and it works fine.

There is a separate sensor that must be placed outdoors to transmit the outdoor temperature to see the outside temperature reading on the device. This is one of those handy gizmos that you didn't know you needed until you have it. It really works quite well to know the outside temps as well as the indoor reading.

I can't remember what the instructions indicated. But, looking at the sensor I would say it is very water resistant. If you are worried about rain, sleet and snow you should have no problem. If you are sticking it in your aquarium it will let the water into the battery/electrical compartment. Having said that I guess you could use some"big stretch" silicone at the seams.

According to the manufacturer, it can transmit up to 100 meters. Hope this helps.