Best Flip-Up Backup Sights for AR-15s (Live Prices)

Short answer: for most AR-15s with a red dot, the Magpul MBUS (polymer) is the budget pick and the Magpul MBUS Pro (steel, about 0.38 inch tall folded) is the pick for a hard-use rifle. Want a range-adjustable rear? The MBUS Pro LR and KAC Micro 600 m have 200 to 600 meter elevation. Running a magnified optic? Offset sights such as the MBUS Pro Offset sit at 45 degrees so you roll the rifle to use them.

Flip-up rear sights compared

Specs are from Magpul and KRISS, read October 2026; the KAC details are from retailer listings.

What to look for

• Steel or polymer. Magpul makes the MBUS Pro "all-steel" with a nitride finish; the MBUS 3 is impact-resistant polymer and lighter (1.06 oz vs 1.80 oz for the Pro rear).
• Folded height. A low folded sight hides under a red dot: about 0.38 in for the MBUS Pro rear, 0.55 in for the MBUS 3 and 0.56 in for the KRISS.
• What adjusts where. On Magpul sights the rear adjusts windage and the front adjusts elevation. The KRISS rear adjusts elevation (0.75 MOA per click). Range-drum rears such as the MBUS Pro LR and KAC Micro add 200 to 600 meter settings.
• Apertures. Most rears flip between a small aperture for precision and a large one for speed, for example 0.07 and 0.19 in on the MBUS Pro.

Do you need a front sight?

On a flat-top upper with a free-float handguard, yes: the front sight goes on the handguard's top rail (see M-LOK vs KeyMod vs Picatinny). If your rifle has a fixed front sight base on the gas block, you only need a rear. Offset sights are sold as pairs: Magpul says the MBUS Pro Offset rear works only with its offset front.

Co-witness with a red dot

Folded up behind a red dot, the irons either line up in the center of the dot's window (absolute co-witness) or in its lower third (lower 1/3), depending on how tall the red dot mount is. See best AR-15 red dot sights and red dot vs LPVO vs prism for the optic itself.

Flip-up backup sights, with today's prices

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Compare all sights and optics, or plan the whole rifle in the AR-15 builder.

Frequently asked questions

What are the best flip-up sights for an AR-15?

The Magpul MBUS Pro for a steel set, the polymer Magpul MBUS on a budget, and the MBUS Pro LR or KAC Micro 600 m if you want range adjustment.

Are polymer flip-up sights durable enough?

Magpul calls the MBUS 3 impact-resistant polymer and sells it as a backup sight. Steel sights such as the MBUS Pro and KRISS are heavier but tougher.

Do flip-up sights co-witness with a red dot?

Yes. Whether you get an absolute or lower 1/3 co-witness depends on the height of the red dot mount.

Do I need a front flip-up sight?

Only if your rifle has no fixed front sight base. Flat-top uppers with free-float handguards need one on the handguard rail.

What are offset sights for?

Offset sights sit at 45 degrees beside a magnified optic, so you roll the rifle to use them without removing the scope.

Which sight adjusts windage and which adjusts elevation?

On Magpul MBUS sights the rear adjusts windage and the front adjusts elevation. Range-drum rears such as the MBUS Pro LR adjust both.