Description Replacement External Sensor Please note that in order for us to send the correct replacement sensor for your system, we need the model number and the serial number of your system. This can be found at the bottom of your monitor. Examples of what the serial number looks like can be found below: 18I0049894 19K0235423 20J01595735 21K00327351 22B0148114 Please be sure to add your model number and your serial number to the “notes” section when placing your order. This can be found at the bottom of your monitor.
