Replicator 2, CTC, extruder upgrade compatiable with 12mm V-groove Filament Bearing

-This extruder upgrade works with V Groove Filament Guiding Bearing (3x12x4mm) as well as a normal flat Bearing (3x10x4mm)
-Designed to work with a CTC model 3d printers (all replicator 2 clones) the arm is very narrow at the tip. This allows it to be used in printers that have a cover on top of the extruder motors (in other designs the thickness prevents the spring from exerting enough pressure on the gear)
-The base of the extruder is flat and the arm sits on a metal washer (less friction