Any one familiar with this

[joe Beadles]

Trying to replace a 3 piece faucet in my bathroom. Going underneath the sink to unscrew the lock nut to release one of the two faucets - I found this thing. No idea what it is or if (how) i can remove it. Unable to remove the faucets as a result. Home Depot folks didn't know either. Any help would be appreciate

 

[jeffmattero76]

I am no expert, but I would look above the sink for the way to get that off. It looks to me that the U shaped brass piece in your picture is meant to span the hole as you tighten some type of nut on the top of the sink.

Trying to replace a 3 piece faucet in my bathroom. Going underneath the sink to unscrew the lock nut to release one of the two faucets - I found this thing. No idea what it is or if (how) i can remove it. Unable to remove the faucets as a result. Home Depot folks didn't know either. Any help would be appreciate

 

[Mr_David]

Pull the pop-up rod out and find an allen/hex wrench that will fit down inside the hole the rod came out of.
maybe about a 1/4 " hex.
That valve unit is dropped through the hole in the counter top and kind of works like a toggle bolt.

and 2nd look at your pictureI might be wrong about the allen wrench but I am preety sure about the toggle part
Jeffmattero is also right. I think the allen wrench part was fro the spout.
take off the trim on top and show us a picture if you can