This is a prusa carriage that's designed to fit directly onto an MK5/6 hotend by Markerbot. I also included mounting holes on top to fit either the standard drive, or an alternative like: http://www.thingiverse.com/thing:7113This version is designed for linear bearings (LM8UU). I borrowed the holders from digifab: http://www.thingiverse.com/thing:8900There are holes on each bearing for zipties.I also included holes on either side of the carriage for optoflags.This version is for a prusa. I've got another version for the mendel as well: http://www.thingiverse.com/thing:10106Edit: fixed belt holder spacing