While it's a very nice Neck, it's also 20 iLvL's below the max (that we know of). I'd wager you could easily get 150-200K for it on most Realms, but much higher for Realms that don't regularly have that high of iLvL listed on the AH. The flip side is if your particular Realm happens to often have 860-885 or so items listed, it might be difficult to get a super high price.
Take my comment with a grain of salt, because I don't flip high value items for massive profits like some do (because I feel it negatively effects the Twinking Community). Instead I flip lower value items for modest profits, like buying 840's for 15K and relisting them at 20K kind of thing. I do however see the pricing on over a dozen unique AH's daily so have a fairly good handle on what items will actually sell for.