Package: 1pcs hotend with cooling fan 1pcs 1meter 12V 40w Heater 1pcs NTC 100K 3950 thermistor Filaments color Switching Backing waiting distance: not less than 45mm Erase tower volume: Not less than 55mm Color switching is fast and stable, without significant print quality defects. Firmware modification is simple and easy to use. Users can easily achieve 3 or 2-color printing. And it can also be used as single nozzle hotend kit.