Yep, Tenebraex or AADMount. I have both, both have their merits. I have had some really, a lot of emphasis on the "really", well used, possibly abused, Tenebraex caps rotate down obstructing my bolt manipulation during recoil. AAD Mount caps are a little stiff to close, and it takes some force to fully close. My only gripes on both caps, which I think are insignificant in comparison, but still need to be mentioned.