The hotend with stainless steel nozzle has a special all-in-one design only for Bambu Lab 3D printers. The nozzle is integrated into the heating block and connected to the heat sink via a thin metal tube for optimal performance. This design allows the hotend to heat up much faster than a normal hotend, and the all-in-one design minimises problems that can occur when replacing nozzles. The heat sink is made of aluminium alloy with high thermal conductivity, and the neck is made of TC4 titanium alloy. Note: 1. if you want to assemble a complete heating element for the X1 series, you must also purchase this: Ceramic heating element - X1 series Thermistor - X1 series Cooling fan for hotend - X1 series Silicone sock for hotend Or you can directly purchase the complete hotend assembly with stainless steel nozzle - X1 series. 2. if you want to assemble a complete hotend assembly for P1S, you also need to purchase: Ceramic heater and thermistor - P1S Cooling fan for hotend - P1S Silicone sock for hotend Or you can directly buy the complete hotend assembly with stainless steel nozzle - P1S. Installation Learn more about replacing the hotend: Bambu Lab Wiki . In the Box only Hotend with stainless steel nozzle Thermal Grease Silicone Sock * 1 M3-14 Step Screws * 2 Compatibility X1 and P1 Series.