An overview video of this magnifier from Valken Airsoft and available at their online store... "The Valken 3x Magnifier Scope with Universal Flip-to-Side Mount can be used in conjunction with red dot sights for long-range aiming or observing. It can also be used as a handheld 3x monocular too. This optic magnifier utilizes the reticle from red dot sights as the aiming reticle, eliminating the need for re-zeroing when shifting between non-magnified and magnified aiming. This magnifier also comes with a picatinny mount that has adjustments to make easy aligning of the magnifier and sight quick and easy. The universal mount also allows for quick flip-to-side action for either the left or right side."