Abstract: A fastening unit for attaching a first beam to a second beam is provided, wherein the second beam is arranged substantially perpendicularly to the first beam, the fastening unit having a first axis and a second axis, wherein the second axis is substantially perpendicular to the first axis. The fastening unit comprises a connecting member extending in a direction parallel to the first axis of the fastening unit and having a first edge portion, a second edge portion and a central portion, the connecting member further comprising a coupling element.