Printrbot Bed Adjustment Knob Spring Clip.
For use With http://www.thingiverse.com/thing:103519. Requires drilling a hole in print bed. In my case, a homemade aluminum bed. Expand picture to see spring clips.
For use With http://www.thingiverse.com/thing:103519. Requires drilling a hole in print bed. In my case, a homemade aluminum bed. Expand picture to see spring clips.