Any 1 wire or 3 wire O2 sensor will work with the 18mm bung. Just cut off whatever end is on it and replace with toyota wire connector (seperate 2 wire connector for the heater if you go to 3 wire)
I changed my stock 1 wire to a heated 3 wire to make it more reliable (no weirdness at idle as the O2 sensor stays hot)
You crimp the connector on the sensor wire as solder will close up the O2 path that the sensor needs to work correctly (O2 flows between the wire strands to the sensor)