I have two of them that I used to create extension wings for my Kapex. Attached them to 12mm Baltic birch with Incra fences. Worked well, but haven’t used them since I picked up the Festool KA-UG-R-L extensions. I prefer them because of the metric scales.
The Multi Blades brackets attached similarly to the Festool offerings and held my extension tables securely. The knob on the Multi Blades bracket is easier to tighten if you have the Kapex mounted on the MFT 3 Kapex as I do.