Magnifiers give you the option to use a zoom if, for example, you have chosen a reddot without zoom.
The Magnifier is placed between you and the reddot and depending on which Magnifier you choose you get 3 or 4x zoom. The advantage of these Magnifiers is that you can flip them to the side so you can choose whether you want to use the zoom or not.
The Magnifiers we have in our assortment are from brands like Aim-O, Leapers, Pirate Arms, Sightmark and Vortex Optics, this last one has a lifetime warranty.