Aimpoint 3X-C Magnifier.

The Aimpoint® 3X-C was developed for the civilian end user, and can be used in conjunction with all Aimpoint® sights for long-range aiming or observation. A variable (-2 to +2) dioptric setting allows this magnifier to be adapted to the individual shooter's eye.
The 3X-C can also be used as a handheld 3X monocular. Aimpoint magnifiers utilize the red dot in Aimpoint sights as the aiming reticle, eliminating the need for re-zeroing when shifting between non-magnified and magnified aiming.
The 3X-C is encased in a shock absorbing protective rubber cover that also creates an ideal ergonomic grip. Internal optical adjustments make aligning the magnifier and sight quick and easy.