This is a 2m (6.6ft) RTD PT-100 type thermo sensor. It provides "0.1 degree" resolution and works well with most PID or solar temperature controllers. Max temperature: 400'C Tip/ 280'C wire. Tip diameter is 5mm. Tip is 4 inches(100mm) long.
Note: this probe should be dry. Do not submerse the whole probe inside the water or it will get damaged. If you must use it to test fluid temperature, make sure that only the tip touches the fluid and must clean it after use.