i ordered three of the cheapo $ 29.97 telestocks from Sportsmans Guide. There's a bit of rattle, but not nearly as much as with the original equipment aluminum atrocity on my formerly pre-ban Eagle Arms AR.
But that's not all. Two of them functioned properly, but the third would not properly lock into place. Put a bit of pressure on it, and it would collapse. But as it happened, I had a spare telestock. So I took the plastic part off the buffer tube (or stock extension, if you prefer), and swapped it out for the other one I had on hand. It worked fine.
Bottom line--For about $100, I got two complete and functiuonal telestocks, plus one complete buffer tube assembly. I've paid more than that just for the buffer tube assemblies.