Actually..... I'm brand new here but I just got this rail, put it on and used it yesterday. I'm a newbie so take my opinion with a grain of salt. The rail gets decent reviews online (amazon). And I, not familiar with AR's at all, was able to drop it in in about 10 mins.
Well... I was all set to show off the handguard I got and send you a link and it seems the seller has taken them off amazon for the moment. Not sure why.
If it helps, here is the seller on Amazon:
Amazon.com At a Glance: Tactical Military Gear
and this is what they listed the rail as (I'm getting this from my recent orders on Amazon):
Ultimate Arms Gear AR-15 AR15 M4 M16 Carbine Rifle Machined 2 Piece Aluminum Accessory Mount with Forward Extension Extended Slots
When I google image search that I get this image which looks exactly like what I received:
So it comes in 3 pieces. The top half seats down inside the delta ring like any other drop in, and goes above/in front of the front sight. Then there is a 2nd piece (bottom half) that goes up until the front sight and a 3rd piece that goes in front of the front sight to complete the setup.
As the reviews on Amazon stated (which you can't see now, unfortunately) it does add some weight. But I do have 2 picatinny mounted items on it now a Magpul AFR (of reputed good quality) and a cheaper 1" flashlight offset mount (of questionable quality) and they both fit fine so I assume the machining is done well enough.