A Stainless Steel clip for the Convoy Series of lights. It's compatible with the S3, M2, and C8. Having said that, I put it on an S2+ and it worked fine, so any of the convoys with the dual lanyard holes at the top may work.
Tip: If the clip is too loose or tight you can take it off and bend it slightly at the curved part.
We also sell a friction fit clip if you prefer a less permanent solution.