Looking for a nozzle solution that will let you print through large amounts of abrasive filaments such as carbon fiber, iron, glow in the dark, or glass filled materials without any wear?  

E3D has done some great studies to determine that printing with as low as even 250g of carbon fiber filled filament can damage the nozzle.  

They have developed this hardened steel nozzle as a solution.  

It is available in 0.25mm, 0.4mm, and 0.8mm sizes as well as 0.8mm 

Need 1.75 Hardened Steel Nozzle Look Here!

The cross sectioned nozzle on the left is brass and has printed 250g of carbon fiber filled filament.  The cross sectioned nozzle on the right is hardened steel and has printed over 2500g (2.5kg) of carbon fiber filled filament with no significant wear.