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AR-15 A2 Rear Apertures

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Master Sgt. Paul Howe's (USA - Ret.) CSAT aperture provides the shooter with both a traditional notch and post for a 7 yard zero, plus a small aperture for a 100 yard zero, allowing the shooter to account for the 2.5" offset between those distances. Rear sight also includes a same plane large battle sight aperture, allowing the user to flip the sight for a wider field of view while maintaining zero.
Fits in Gen 2-3 TROY bases (Gen 1 bases need screw kit from XS®). Does not fit Ozark Armament Micro Flip Up BUIS.
Made in the USA.

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Prop 65 warning WARNING: This product can expose you to lead, which is known to the State of California to cause cancer and birth defects or reproductive harm. (For more information go to

Non-Tritium Products — XS Sights warrants all non-tritium products to be free from defects in material and workmanship. This warranty applies only to the original purchaser. Proof of purchase is required for an RMA. If this product is found to be defective, the manufacturer's only obligation is to replace the product at the manufacturer's discretion, provided that the product has not been damaged through misuse, modifications, neglect, or mishandling. This warranty shall not apply to the finish on any portion of the product or weathering, as this is considered normal wear and tear. Sights improperly installed are not subject to warranty. — XS Sights only warrants products sold through authorized resellers. — All international sales are final and do not qualify for this warranty policy. Some authorized international resellers carry common warranty items to provide for their customers. For more information, please see our International Shipping Policy.

3 Reviews

  • 5
    Traditional cant-go-wrong option

    Posted by J on Feb 23rd 2022

    A well machined dual aperture, same plane so your zero is unaffected. No burrs or defects. Note that it has a large peep sized at .230, small peep at .100, so it's slightly oversized from the milspec of .200/.070, but I happen to like the XS size because you do get increased visibility and lighting at the theoretical cost of slight accuracy, so the tradeoff is worth it. Screws into mil-spec rear sight hardware without issue. Great to have this option.

  • 5
    AR-15 A2 Rear Apertures

    Posted by Frederick Duncan on Feb 19th 2022

    One of the best things I've added to my S&W M&P-15! Now I can switch between apertures, and the POA and POI doesn't change all over the place.

  • 5
    Does its job!!

    Posted by Max on Nov 23rd 2021

    Looks great, zeroed well, the larger aperture works great with a red dot co-witnessed.