'trolley/pulley thing', used by contractors to hang overhead utility cables

I don't know if there is a correct term for this device -- and in fact only accidentally know what it is used for, having seen multiples of them actually being used, probably a couple years or so ago now and the last time in recent memory when contractor's crews in bucket trucks spent the better part of a week keeping assorted lanes of the busy street behind my backyard blocked off with cones (and royally screwing up the typical traffic, including me) while they were otherwise adding additional cable to the existing row of utility poles. I'm pretty certain it was communications cable, not electric power anyways, which I'd guess would require different sorts of equipment.

Anyways -- a big truck with a huge spool of the new cable on it would be creeping along from some-or-other starting point, unspooling the new stuff as it went, and bunches of these little gizmos would get used to temporarily help hang the new single cable from the existing bundle, being subsequently clipped over it (notice the 'thin' side that's only fastened at the wheel end, allowing it to do that) by a guy in a bucket who'd then drop the nylon strap back down to ground level where other workers would help guide it into place along and under the others -- then another truck in the parade with another dude in a bucket would *un*-clip these things, just before yet one more big truck with another big spool of (much smaller diameter) wire on it would come along, that one also pulling a really neato-looking 'spinny' kinda little machine along behind it up there that'd spiral wrap its smaller wire around the whole mess, thus binding the new cable to the existing bundle and ultimately leaving everything (but the traffic) looking basically just as it had been before. (though exactly one cable bigger)

And, as mentioned, I did have plenty of chances to observe their process, that week sitting in traffic... <groan>

It was months later when I went exploring on the other side of my fence, shortly after a particularly dramatic traffic *accident* had occurred, to look and see if any cool former auto-bits had been left behind. There weren't, but I found this thing laying there in the ditch instead, pretty much exactly as it is shown here wrapped up on itself. I'll never use it for anything and frankly don't even really know why I picked it up, except that it was there and I recognized it...?? <lol>