The Bluetooth Finder distance bar shows approximate location and distance from you and device you are trying to find.
The distance bar will move back and forth depending on how close you are. The signal to your device depends on the type of environment you are trying to find it in.
For example, you are trying to find your Pencil or device at home. Your home may contain may walls and rooms. The distance bar will fill in some rooms and not in some. You may have to keep looking in all rooms to see where the distance bar is the fullest. After you have determined this, you will be able further search in that room for the device as the distance bar will be more accurate.