I've never seen the need for comm units. We just don't talk much I guess. Everyone knows what to do and when to do it without being told. Even on crane jobs, we have a quick chat before we start but then it's pretty much everyone simply does his job. A few hand signals perhaps now and again but not much conversing.
I keep talking about getting them, but the complexity puts me off, you have to buy a certain helmet and fit the things yourself I think (if I’m wrong, I’m wrong, don’t ask me to go back through this thread!)
What I want is to be able to buy the lot, pull it out the box, put it on my head and go.