You can pair up to six Aquatel T110 Tank Sender units to any one D110 display. These have a standard working range of up to 300m (1000 feet) line of sight, But when used with an Aquatel custom booster antenna, you can achieve up to 10km (6 miles) line of sight. See links to Aquatel booster antennas at the bottom of this page for more details and options.
You can have trees, buildings, concrete walls, floors etc between Tank and Display units, however range will be shortened.
Manufacturer Recommended Batteries:
In environments where it is likely daytime ambient air temperatures will exceed 110 Fahrenheit (45 degrees Celsius) and where the Tank Sender Units are exposed to direct sunlight, Aquatel recommends a cover be placed over the tank sender unit to avoid batteries overheating and damaging the Tank Sender unit. ?They also recommend the use of Energizer Ultimate Lithium Batteries in all of theirTank Sender units.