From mid-June 2016 E3D Hotends will transition to using a standard cartridge-type format for temperature sensors. This means a new heater-block and thermistor cartridge will be supplied with the E3D-v6 as standard. For a full explanation read the sensor documentation page.
This kit is intended for those with some experience who may already have many parts included in the full kit to hand already. This kit requires extra parts such as electronics, wiring, etc to complete its functionality.
If you are at all unsure as to whether you should order this or the full kit you should purchase the full kit as it contains all the parts required to create a functioning hotend.