The original model breaks easily when you hit the E-stop with it in the holder so, I redesigned the model. I re-designed it to be mounted flush against the extrusion so that it's supported and won't break if you need to hit it. After mounting mine with only 2 bolts, I noticed that it was very secure with only the top 2 so I saved the hardware and didn't use the bottom holes. I made 2-hole and 4-hole versions so you can choose but the top 2 is plenty. I also thickened the walls by 1 mm, added interior fillets to strengthen it, and tightened up the fit just a tad - there's still plenty movement.