A 1.2mm MK8 extruder nozzle is a type of nozzle that can be attached to the extruder of a 3D printer. The nozzle is responsible for heating and extruding the filament into thin layers that form the 3D model. A 1.2mm MK8 extruder nozzle is made of steel, which is a metal that has good thermal conductivity and corrosion resistance. The nozzle has an output diameter of 1.2mm, which means it can produce thicker layers and faster printing speed than smaller nozzles. However, it may also result in lower resolution and accuracy than smaller nozzles. The nozzle has an input diameter of 1.75mm, which means it can work with filaments that have a diameter of 1.75mm, such as PLA, ABS, PETG, etc. The nozzle has a screw thread of M6, which means it can fit into the extruder with a M6 thread hole. The nozzle also has a hexagon diameter of 6mm, which means it can be tightened or loosened with a 6mm wrench or spanner.