This is the largest 2-pc wire puzzle I've ever seen.

Here is what I call a simply, tricky puzzle :
. . . simple, once you know how it works.
. . . tricky, in its simplicity.
The 'key' maneuver is hidden in plain sight.

The wire is a whopping 1/4" thick.
It weighs 200.3 grams (7.05 oz) (.441 lb)

Set flat on a table surface (free of tension), it measures
5 + 7/8" long.
Under tension, you could pull it another 3/8"
(for a total of 6 + 1/4" in length)

<<< Starting position

Notice that the loop ends of the U piece are wrapped around the 'top' stem of the C piece >>>

Pull the U piece up and away from you

Note :    there is a slight amount of force necessary to get you through this part. You'll notice that when you start this maneuver, there is a slight springy 'give' to it -- as contrasted if you were to start with the two pieces upside down like in the pic to the right

. . . there would be NO 'give' at all .

When you've pushed it back . . . and down . . . far enough, the U piece will  'shudder'   itself free of the C piece . . . at which point you can maneuver the U piece sideways

(If, at first, the release does not take place, just give the U piece a push from the backside -- the main curve)

. . . first, one side

. . . then the other

. . . until . . . Voila!    The pieces are free.