This thermowell is not a product that can be used as a stand-alone. This is specifically meant as an optional back end to the Blichmann Brewcommander Temperture sensor bulkhead assembly. When installed in combination with that bulkhead, it allows you to insert or remove the temperature sensor from your vessel while it remains full.
One use of this functionality is to move the sensor/probe from one vessel to another such as from the HLT to the Boil Kettle when your system can only use one heater at a time. To do this, you'll need both vessels to have the sensor bulkhead AND this thermowell installed in each vessel.

The other way to achieve the same end is to install a sensor bulkhead AND sensor into each kettle and swap the male plug at the back of the controller. This negates the temperature lag time of using a thermowell.

THE PHOTO SHOWS THE UNIT IN TWO DIFFERENT ANGLES BUT YOU ONLY GET ONE WHEN ORDERING THIS.