This is off a BA-22 or BA-25 military parachute.
You can see the two quick release latches in this photo, one on each shoulder. Note that the disconnect portion is gone in the prop and the wire release ring is exposed (not stowed as in this photo).
Being a skydiver and seeing those old snap releases just makes me shiver. The older style rigs and equipment use to use those to disconnect the main during a malfunction. Basically you had to look up, flip the release and then pull the tabs to break away from the bad parachute. Then reenter freefall pull the reserve pint and then punch (yes Punch) the reserve out of the reserve delopyment bag which would have been sitting on the belly. Lots of horror. Nowadays there are two handles. One to release the Main and another to deploy the reserve. The whole thing is over in a matter of seconds with a new canopy over your head.
Sorry about that Replicator1701, as was mentioned above, it's from the Prop Store of London which is a prop clearing house that deals in screen used pieces and has been listing a lot of Serenity items over the last month or more.
You can see their watermark on all the images that I posted.