【Standard Replacement for Prusa mk4】This aluminum block is a clone of the hotend assembly made specifically for printers using Nextruder: Prusa mk4 & mk3.9XL Series. It's so EZ to set up with a heating element, temperature sensor, nozzle adapter, and steel nozzle 0.4.【Value Package】What's in the package? Just an aluminum heating block & enclosed M3 Stud Bolts & Silicone Cover Sock- just all you need.【Quality Material】Select pure aluminum block & quality heat-resist silicone sock for our customer. It can handle high temperatures well and delivers even more precise and stable performance than your old one.【Quality Service】If you need other MK4 clone accessories parts like heater cartridge heatbed thermistor kit or nozzle ir sensor, just search for our store Yhobuy. Half Price Twice Quality, our small business aim to provide best product always.