Magpul Industries MBUS Back-Up Rear Sight Gen 2, Fits Picatinny Rails, Flip Up, Black MAG248-BLK
Specifications:

Type	Rear
Frame Material	Polymer
Frame Color	Black
Firearm Fit
Base Configuration	Picatinny Rail
Style	Folding
Front Material
Rear Material
Front Color
Rear Color
Rail Size
Windage Adjustment	Yes
Elevation Adjustment
Fiber Diameter
Firearm Type	AR15/M16