Not really a "sighting jig" as the BIL describes, but a mechanical rest for a bench gun. Also, I don't see much lathe work, but instead see mill and press work.
Don't know about you 70CB, but I've not seen a lot of 1k yard shooters use aluminum as a rest, as they prefer weight over size. Interestingly, the forend shape of that rest relies on a non-flat stock, which is quite contrary to a bench rest gun. All of my bench rifles use a 3" flat stock to ride the bag smoothly.
It's a neat gadget, but I doubt any serious shooter would pay $150 for something that isn't essentially designed for serious shooters. Who knows, maybe the novelty of it persuades a buyer.