It is the upper with the full quad rail and has the chrome lined barrel of the original 556, but with the black BGC and the plastic sights from the E model.
Overall very good shape, maybe 1000 rounds or so through it.
You get a carry bag and 3 x 30 round gen3 PMAGS with it too.
You can see all the details on the Ruger site here: http://www.ruger.com/products/sr556/index.html?r=y
I'm going to guess at a price that is between the 556 and the 556E and ask $1200 for it.
Act now and I'll throw in 10 rounds of M855 at no additional charge! (A $50 value
)PM if you'd like some photos and I can send them via email or phone.
Thanks for looking!