Summary

Allows you to butt two 20x40mm OpenBuilds or regular extrusions end to end. Use M5X10 Socket Head Cap Screws (http://www.mrmetric.com/M10089) and M5X.8 Square Nuts (http://www.mrmetric.com/M53065) to attach.

You will need 24 of each.

I added a 0.5mm gap all the way around the inside to compensate for printers printing inside dimensions too small.