I have an older Bushnell Hallo-site which is the same as Eotec 511 except for no extra hood and no screw holes to mount one. A small drill bit into the aluminum rail of the Hallow-site using the hood mounting holes as a guide resolved that short coming. It fits perfectly and turns the old Bushnell into an Eotec. I wish I had seen this before. Note, the mounting screws come in the package with loc-tite already applied to create a tight bond and those screws are hard enough to tap the soft aluminum rail if you drill the holes just slightly smaller than the screws. No need to buy additional screws.
Pros: Fit
Cons: none
This review was written in the old system and had content requirements that are different than reviews written today.