From TheFirearmBlog, I never knew these existed. The above picatinny rail mounted mirror is the Diamondhead Versa-view mirror sight, it’s basically a mirror that you can angle to allow you to shoot around corners without exposing yourself to the enemy.
There is also the Mirror Sight from X-Caliber Tactical that also has a dual aperture sight built-in when not using the mirror, check it out in action below.
