Luth-AR A2 Rear Sight Kit Black. Complete A2 rear sight kit. This kit requires assembly and will mount on an A2 upper receiver. Specifications for Luth-AR A2 Rear Sight Kit: Manufacturer: Luth-AR Gun Make: AR Platform Gun Model: AR-15 Sight Position: Rear Front Sight Color: REAR SIGHT ONLY Rear Sight Color: Black Gun Type: Rifle Color: Black Package Contents: Luth-AR A2 Rear Sight Kit A2 Rear Base Lug A2 Rear Sight Aperture Rear Base Flat Spring Rear Base Windage Knob Screw Rear Base Windage Knob Rear Base Spring Pin Rear Base Spring Rear BaseBall Bearing Rear Base Index Elevation (8/3) Rear Base Elevation Knob Rear Base Elevation Knob Spring Rear Base Spring Pin Rear Base Index Screw What firearm models does the manufacturer say Luth-AR A2 Rear Sight Kit is compatible with? The manufacturer says that Luth-AR A2 Rear Sight Kit is compatible with AR-15Luth-AR UR-21K: A2 Rear Sight Kit Black