Harold, I am not sure any support hardware is actually required to be listed. (as noted with the Unistrut example above)
I do know I got the Carlon guy to admit the RNMC straps were *not* UV protected (nor do they seem to have a listing mark on them)
The Halex 1/2" EMT "one holers" do have the mark. I am guessing the older technology got listed some time in the past (maybe for a government bid) and the listing still stands.
I use some common sense on these things. Being listed would not keep them from being improperly installed and an unconventional strapping method might be superior in some situation. The operative word is "secured".
BTW I am not thrilled with Tywraps. In an unthreatening situation like simply securing wires out of harm's way, in a wall cavity, all other things being safe, until it is closed up, I will tolerate them, but I am not going to live with them in exposed work. They fail too soon in my experience.
Black ones are better than white ones but both fail pretty quickly if the sun hits them.
