This is a x-belt holder for an GT2 belt for the Anet A8.
There are GT2 belts with 1.3 and 1.4 mm, so check yours before printing.
Original Anet A8 belt is even
...Plus thicker.
I based this on this ( http://www.thingiverse.com/thing:2016779 ), which I couldn't slice with simplify3D.