Prototype Supply High Lubricity Wear Resistant Nozzle Upgrade MK8 0.4 mm - For MakerBot and RepRap Hotends with M6 threads Compatible replacement for use on MK8 and MK7 type hot-ends with a M6-threaded heater block (the hotends for MakerBot Replicator 2, 2X, and 1). Hard coating improves service life and reduces down time Standard 0.4 mm nozzle hole diameter Highly recommended for use with abrasive filaments (metal filled, glow-in-the-dark, carbon-fiber filled) Also recommended for use with clog-prone filaments (fiber filled, PVA)