Carpenter Square holder for IKEA Skadis boards. Mounted using the T-Clip System by Line Arc Line. Can also use T-Clips mini by capze or Low Profile T-Clips by tchoupshop to fit flush. The clips come in two versions - one for black/white Skadis boards, and one for unpainted ones. (not included here; please download from the creator).

I made a T Clip tool to make turning the clips easier, especially the flushed version. After having this one I now only go for the low profile ones.