something has broken off one of these figure's found this at the bottom of the cabinet and I can't see which one it has come off , probably a long shot but thought this might be the best place to ask , it's about 17 mm in length
Based on the color, look closely at your 4-LOM and IG-88. Also, it could be a gun part, like the scope on one of your Stormtrooper blasters. Good luck!