Very affordable - Leapers UTG ACCU-SYNC Top Mounted Deployable Iron Sight

Very affordable and well made back-up sights. Made of aluminum and constructed nicely. I’ve purchased several of these and they work very well. I did have an issue with installing this on one of my handguard as the groove width was narrower than usual. I ended up swapping it with another one on another AR I have and then it fit well. Non-USA handguards seem to be made with slightly different dimensions and don’t always fit the same. The front sight is adjustable up and down with a standard AR/M-16 type front sight adjustment tool. Well made and very affordable.