Some notes on that thing, and putting it on your .308AR...
It's lighter, stronger, and cheaper than the original UBR, BUT... It has a different receiver extension that it's made for. That's really it's big deal. It's VLTOR A5-lengthed extension, which is Armalite AR-10 Carbine-lengthed extension. That extension has an internal depth of 7 5/8", versus the original UBR and it's included special extension, at 7" internal depth. Which is GOOD! BEST way to run a collapsible-stocked .308AR, in my worthless opinion.
For you to run it on your .308AR, you need to do a few things with it:
REMOVE the included Buffer Spacer that comes with it - you cannot - CANNOT - use that with your Big AR.
Definitely use the only buffer spring that's really made for this setup - the Armalite EA1095 AR-10 Carbine buffer spring. That little dandy is available at DSG Arms, and other places. I get mine from DSG when I need them.
For buffers, make damn sure you use (at least) an AR15 H3 buffer. Yes, AR15 buffer. H3-weighted at the lightest. Get one anywhere, they're all the same for the most part. Might as well toss it in the cart at DSG, when you snatch up the spring.
You will love the UBR - I only have one of them, on a 5.56 gun, but I love the thing.