Great rear sight for most people - Leapers UTG Top Mounted Deployable Rear Sight

Purchased due to it not being made of plastic type material. Paired with the matching front sight mounted to the gas block rail on an M&P 15 Sport 2 is a perfect co-witness through the cheap CTS-103 red/green dot. Especially like the dual aperture which feels like it provides the accuracy of an M1 Garand at range but the both eyes open sighting of a Ruger PC9 as closer ranges. These are not spring loaded like the most popular produced by Magpul or Ruger, but they’re easy to flip up when needed. Maybe not the best for tactical situations, but for range and stand your ground uses I think they’re just fine.