Ring Mailbox Sensor Range

What is the range in distance for the Ring Mailbox Sensor? I have Ring Pathway lights and bridge, but a long driveway (which is why I'd be interested to know if mail has been delivered.What is the wireless protocol? If it is one of the community shared protocols, that's helpful to know though I'm rural so I don't believe it would yet benefit me to bounce off of the units of other people's devices.