Gravitrax spacer Lego compatible

Gravitrax spacers which can be used together with Lego Bricks. The spacer with the connected knobs is easier to print. Please use the files just as an inspiration. Most likely you have to adjust the design. The Lego studs and holes have to be exact to a fraction of a millimeter. It's very unlikely that the combination of these STL files and your printer produces good results right away.