The NcStar AR-15 Detachable Rear A2 Iron Back-up Sight (dual aperture) is precision-made with aluminum and steel. The fixed A2 design is adjustable for windage and elevation and it mounts onto Weaver and Picatinny-type rails.
Specifications:

Type	Rear
Frame Material	Aluminum
Frame Color	Black
Firearm Fit	AR-15
Base Configuration	Picatinny Rail
Style	Picatinny
Front Material	N/A
Rear Material	Steel
Front Color	N/A
Rear Color
Rail Size
Windage Adjustment
Elevation Adjustment
Fiber Diameter
Firearm Type	AR Rifle