Guy
MK8: Valid for printers with hotend MK8 (Ender 3, Ender 3 PRO, Ender 5, CR-10, Anet ET4, Anet A6, Anet A8, Geeetech A10)
Mk10: Valid for printers with hotend MK10 (Geeetech A10M, etc)
E3D: valid for hotends E3D and clones (Prusa Mk3, Anycubic Mega, Anycubic Chiron, etc.)
Volcano: valid for hotends E3D Volcano or compatible (Artillery X1, Artillery Genius)
Material
Brass: supplied with the printer, suitable for printing the most common materials (PLA, PETG, ABS, ETC). Exhibit better thermal conductivity than steel nozzles
Stainless steel: suitable for printing objects that will be in contact with food or with the mouth or respiratory tract as it does not contain lead.
Hardened steel: suitable for printing with materials containing chips of hard materials such as carbon fiber, metal, etc. It will last longer with these materials than a standard brass mouthpiece.
Size
<0.4mm: suitable for maximum detail at the cost of increased print times
0.4mm: most common size, with a good compromise between print time and detail
0.5-0.6mm: nozzles commonly used to gain printing speed without a great loss of detail, also used for materials with large traces such as wood filament.
>0.6mm: Used for large prints, the loss of detail is noticeable. For these sizes it is advisable to have a hotend Type Volcano, as the amount of material to be melted per second can be too much for a hotend normal.
For materials that contain traces of hard materials such as metals, carbon fiber, etc., the use of hardened steel nozzles is recommended.