Magpul's MBUS — Back-Up Sight — became the default folding iron sight on AR-15s because it does one thing extremely well: it stays out of the way until you need it, then deploys instantly with a push of a button. The MBUS 3 is the latest generation, refined for a lower folded profile and improved lockup.

This is the rear unit in Flat Dark Earth, with a dual aperture for close and precise work and tool-free windage adjustment. Polymer construction keeps weight down and won't corrode. Every optic eventually fails, loses zero or runs out of battery — a set of backup irons is cheap insurance on any serious rifle.

In stock and ready to ship straight to your door from Dawson Defense, an Arizona-owned licensed dealer.