I've included a printable spring. If you want to replace it with a metal spring the measurements are 40 - 45mm (1.75") by 8mm (5/16"). No supports are needed for this print. I've included the optional "Wall" .stl. It's hollow, but still takes a long time to print. However, he just didn't seem complete without something to peer over;) The wall measures 206.29, 46.97, 164.5.