Portabee Z-axis stabiliser

This is a z-axis stabiliser for the Portabee 3D printer. I used this for the box I've built to use with the printer.
More details here: http://www.igorkromin.net/index.php/2013/05/26/a-clear-acrylic-box-for-the-portabee-3d-printer-part-1-making-the-box/