A generic BC Overpressure Relief and Dump Valve w/o flanges that is compatible with Dive Rite, DGX Gears, HOG (pre-2015), XDEEP, Deep Sea Supply, Oxycheq, Halcyon (pre-2015) and a variety of other technical diving brand BCDs.
It is NOT compatible with Aqualung, ScubaPro, Seaquest, Mares, Mares XR, Halcyon (Post-2015), HOG (post-2015) ,Hollis, OMS (Post-2015), Poseidon, Zeagle or other major brand products.
Initially I thought it did not fit on my Halcyon Eclipse wing, however trying it again it does fit. A bargain at 1/5th the price of the Halcyon replacement. The pull cord is slightly shorter than the standard Halcyon cord, but looks to be plenty long enough to accomplish its job.
After receiving and installing a BC Valve that turned out to be defective, Dive Gear Express shipped me new one immediately. They were very responsive and easy to communicate with via email. Will buy from them again.