AIM AP Style 3x Magnifier
The AIM AP 3x Magnifier is a great choice for those of you want to reach out and get those hard to hit targets. Attaching to a standard picatinny rail, the unit is designed to add a 3x fixed magnification which works in tandem with your red dot optic.
This magnifier as a quick side-sweeping spring loaded action removing it completely so you can switch back to just your normal red dot at the touch of a button. It allows you to maintain the same scope setting and view at range with the 3x zoom but then drop to no zoom should closer targets present themselves.