Hi All - First vent installed - 3 more to fit. Interesting when I placed the black side out it was a totally black plate as the "holes" are black space behind. So white face out shows up the vents. The first 3 vents I cut with a straight 6mm 2F carbide. Was a bit noisy but cut fine., The last one I swapped for a 6mm 1F up spiral carbide. So much quieter and it plunged better. I've stayed away from 1F cutters but I'm starting to tend towards them.... I have some aluminium parts to make and 1F tools are the go... Peter