Replacement Temperature Probe for JBJ TRUE-TEMP Digital Heater Controller. Most heaters have an integrated temperature probe within the same heating element. This can lead to false readings and premature ON/OFF cycles. The TRUE TEMP digital controller is equipped with a remote quick disconnect temperature probe that can be placed up to 5 feet away from the heating element for a comprehensive temperature measurement of the total volume of water. Quick disconnect temperature probe grants easy replacement without the need to replace the entire controller in the event it fails. Magnet Holder NOT INCLUDED.