I found this in the bottom of my gun bag. Don't know where it came from. Possibly from my AR. It's about 1.5 inches long, appx. 1/16" thick x 1/8"wide and has a spring that slides over the longer part and rests on the shoulder near the top. I've checked with my AR friends that have built many and they don't recognize it. The spring slides over the longer curved part and rests against the "shoulder". Anybody got any ideas? May be part of a trigger group just not necessarily for an AR. Any help would be greatly appreciated.