That kinky ring is made to go in behind the lower ring, and is meant to keep the piston centered in the bore. They're rubbish, and every time I've taken apart an engine that was fitted, they were broken in several places. Thinking of what a mess it would make if one of those pieces got loose, I can't bring myself to put the new ones in. I'm not alone in this, lots of people that know a lot more than I do omit them.
I wouldn't bring her home to Mama, but Mama ain't home tonight.