PT1000's are stainless steel high temperature, high accuracy temperature sensors that you can now use on your E3D V6 HotEnd instead of a thermistor or thermocouple.

PT1000's are able to measure higher temperatures than thermistors - upto 500°C. 

PT1000 sensors are also very easy to handle, being of a metal cartridge type construction that is secured with a set screw, no more fiberglass sleeving or clamping washer. 

The PT1000 sensor will fit in the E3D cartridge style heater blocks. 

PT1000's are similiar to thermistors in that you do NOT need an amplifier board.