If you use your rifle platform as a serious tool, a backup sighting system is absolutely imperative for reliability. Modern optics such as holographic sights and specialty scopes adorn many AR-15s today (and these are great tools) but iron sights are the foundation of marksmanship and are ready to go should something happen to your many options.
With as much Picatinny rail space as the average AR has, you can most likely find a little bit of room for an additional accessory. Compact, reliable, and lightweight, the Magpul MBUS Pro fits the needs perfectly.
Although more expensive than the standard Magpul MBUS front sight, the all-steel construction makes the additional cost well worth it for the shooter who wants the additional sturdiness and reliability.
The MBUS Pro front sight folds neatly underneath optics or other accessories and quickly flips into place when needed. When stowed, it sticks out less than half an inch above rail height. Deployed height, however, is standard height for an AR front sight. This means it is easily compatible with your standard rear sights, as well as standard co-witness risers and mounts. The sight is also knob-adjustable for elevation without requiring any additional tools.