They look really quite smart, and certainly seem to get the thumbs up from the electricians, judging by the reviews on there. They don't look like they have a way to fix them down though, in the way you might screw a choc block to a panel. So worth bearing in mind for some applications. Don't some forum members use something similar on DIN rails in their control cabinets? I seem to have seen something along those lines in pics on the build logs.....