Hello We have a cnc router at work that we use for cutting various materials ranging from foam, aluminium, wood and Perspex. We currently have standard ear muff type defenders but are they actually any good? Cutting can be quite loud (even just running the machine without cutting anything is loud). Today my boss cut some aluminium in the cnc room and i was in the room with muffs on but the cutting was going in for a good couple of hours and in the end i decided to work in the office we have in a building next door. I got in a bit of trouble because of this and the boss said it wasnt too loud but to be honest with you, i felt it was, especially for the length of time. I guess my question is which ear defenders would be best for using the cnc?