Luth-AR A2 Rear Sight Kit, Fits A2 Upper Receivers For AR-15 Firarms, Black UR-21K

Luth-AR A2 Sight Kit Rear

MISSION FIRST TACTICAL Extreme Duty Rear Metal Back Up Sight Black

LUTH-AR A2 Black Rear Sight Kit For AR-15 (UR-21K)

Wraithworks Billet Slick Side AR-15 Upper Receiver - Black | No Forward Assist or Brass Deflector

Daniel Defense Rear Receiver QD Attachment Point With Swivel, Black - 03-018-30026

MEPROLIGHT FABS Flip Back Up Sights -Alum Blank Rear/Grn Frt

LBE Unlimited M4 Stripped Upper Receiver, Fits AR15, Black Finish ARSTUP