It says the probe to the "RFX Gateway" uses the 433 MHz band like many key fobs and other wireless devices use. Then it's bluetooth between the gateway and an app on a cell phone.
So... two different type of RF technology used with this thing.
It also mentions something about a cloud (A random computer somewhere in the world that you don't control) connection but I didn't read into that.
Edit: The cloud thing appears to use a connection to a wireless router so that's another type of RF modulation used along with the Bluetooth connection. So it appears to use 433 MHz, Bluetooth for the phone app and WiFi for sending data to someone's computer somewhere in the world.
Sorry for the sanity check. But thanks for the followups. So instead of one comm type it uses three! So a comm error could be fun to shoot! Covid tells me its nap time, bye.