This is a very well made Gooseneck mount that is designed for the Eotech (N or AA batteries) to cowitness with your iron sights. It may fit other optics, I'm not sure. The manufacturer is PRI. It is used to mount sight on a Carry handle upper. I bought it and didn't end up using it much. It is pretty much like new.
Shown below mounted on one of my uppers (for sale in another thread
$80 Shipped and insured SOLD
. These things sell for over $100 new!
Paypal or money order
Please email me with questions or for more pics.
Of course, gotta add that the upper is not included.