EV3 ball caster

Remix of http://www.thingiverse.com/thing:286000
These files have been optimized to work with a Rep2 printer, printing at standard resolution, no raft or support.
For the ball bearing I use a standard mouse ball as seen in the picture. With the rubber on, they are about 7/8"/22mm. With the rubber removed they are 3/4"/19.02mm.
This makes a caster just slightly bigger than the OEM caster ~0.025"/0.7mm
Special thanks to projunk http://www.thingiverse.com/projunk/designs for the original design