This is a full prusa i3 plastic parts kit for M10 threaded rods and 8 mm smooth rods used with LM8UU bearings. Also the bearings for the y and x belt are 624ZZ bearings where the bearings for the extruder are 608ZZ bearings.
The parts are made of ABS plastic. The default color is black.
The holes to mount the extruder block to the x-carriage fit M4 bolts. (Standard is for M3 bolts)
Parts that are included:
Greg's Accessible Extruder Block
Greg's Idler block
Greg's Large Gear
Greg's Small Gear