Note: The Max4 extruder and the filament runout sensor are designed as an integrated module, highly integrated and working together. If the filament runout sensor malfunctions and needs replacement, it is recommended to purchase the entire Max4 extruder assembly for replacement. Disassembling or replacing the sensor component separately is not recommended to avoid installation errors, poor circuit connections, and other subsequent problems caused by module separation, thus ensuring the overall stability and safety of the equipment.