It's a direct drive Bowden extruder for the MK8 drive gear.
It supports both 1,75mm and 3mm filament. Just change your pneumatic fitting (all M5 fittings will fit).
There are 2 versions:
MendelMax version will slide into your aluminium extrusions.
Standard version is for all other printers.
The Hotend mounting plate will both fit into standard x carriages as well as in my Quick change X Carriage
It's designed to be very easy to use and to change filaments but it also offers great stability.
Print it with your favourite settings (I use 60% infill).
For mounting the 608zz ball bearing you could either use the included plastic rod or a steel or aluminium one.