What is this mountable adjustable clamp for a pipe called?

To tell the truth that looks home made to me but it is a pipe strap / clamp. Pro’ s usually use strut clamps , like kindorf, uni strut or power strut. I said home made because of the hole on the top under the bolt, the strap is not flat to the surface on the bottom. I would use 1/2” strut channel and an appropriate rigid or universal clamp. We use these in very large numbers in industry but some residential sparky’s save a few $$$ and bend them out of metal strapping. Your example is better than plumbers tape ... galvanized strip with holes ... used in a loop or similar manner.

This looks like a field retro fit. A larger clamp than was needed and a two bolt holes drilled in it to make it fit. I have never seen one like this before and I've put up a lot of pipe. There are many pipe clamps that have rubber bushings in them to keep them from hitting the walls.

Pipe grip tie is the term used by Simpson for PGT® Pipe Grip Ties® which are used to attach a wood fence to a metal pipe support.