The Luth-AR A2 Rear Sight Assembly Kit (brand part no. UR-21K) is a factory-style rear sight built for the AR-15.

Key Specifications

• Built to fit the AR-15 platform.
• Sold as an assembly kit, including the parts needed to mount and adjust the sight.
• Styled after the A2 fixed rear sight found on mil-spec AR-15 uppers.
• Classified as a firearm part/accessory, not a regulated firearm itself — no FFL transfer required to purchase.

Frequently Asked Questions

What’s included in the kit? It’s sold as a complete rear sight assembly with the hardware needed to mount it, rather than just the sight body alone.

Is this sight adjustable? A2-style rear sights are windage and elevation adjustable, in keeping with the standard mil-spec A2 sight design.

Does this fit a flat-top upper? A2 rear sights are designed for the fixed carry-handle-style rear sight base; confirm your upper’s configuration with us before ordering if you have a flat-top receiver.

Buy the Luth-AR A2 Rear Sight Assembly Kit

Order the Luth-AR A2 Rear Sight Assembly Kit today for fast, insured shipping from a Lubbock, TX gun shop. Browse more Luth-AR parts in our Rifle Parts category.