X carriage Loop

this is a X carriage named Loop:
- for standart linear bearing LM8UU
- standart 50mm M4 fixation holes for extruder
- standart 50mm spaced rod (ex: RepRap Prusa, MendelMax etc.)
- Fan mount integrated
- Strong structure for a rigid ABS print (work as well with PLA of course)
- integrated belt tensionning system (one side only)

it's mainly a variant of http://www.thingiverse.com/thing:9869
what is different then?
- linear bearing are inserted from the side, not from the botto