Remote Wireless Fridge Thermometer

In addition to the temp gauge on my dual compartment fridge I use two wireless thermometers to monitor temps remotely but find them not all that good with reception often being lost.

The first unit is a Waeco branded unit but if the sender and receiver loose contact the do not automatically reconnect as as batteries have to be removed from both units and reinserted in a set sequence. Its range is also poor and looses contact often.

The second unit is a cheap Jaycar unit and actually works well - when contact is lost it reconnects automatically but they only come in one channel so only one unit can be used.

Both units having batteries in the sender unit suffer from lower battery performance as temps reduce in the fridge - particularly the Waeco which range can reduce to almost zero when in the freezer and drops out a lot.

So my ideal would be a sender unit that is external to the fridge so its batteries do not suffer in the cold with a wired sensors that go into the fridge. Ideally a double unit so both compartments can be monitored so the remote receiver would need to display two temps - failing this a single transmitter/ receiver that has different channels so two units can be used side by side.

Does anyone know if such a unit exists and where to get it?

Thanks

Garry