Florian @ sig556reviews.com has posted an extensive review of the TangoDown Model ACB-4 Advanced Combat Bipod.
I finally got my TangoDown Combat Bipod in on Friday after an almost 4 week wait. I put it on my Sig 556 SWAT the same day and took it out on Saturday. I have to say, the wait was definitely worth it.
As a bonus Florian has included a bunch of photos of his Sig 556 rifle.
More here.