Midwest Industries ERS (Emergency Rear Sight) Flip-Up Rear Sight. All of Midwest Industries products focus on providing top notch quality and reliability you expect from products made in the U.S.A. Backed by Midwest Industries Lifetime Warranty.

Features:
A2 style dual aperture
Thick rugged pivot ears
Locking detent with double the locking surface" for maximum strength
Lock detent button with stepped down turns
.65 MOA on M-4 type rifles / .49 MOA on A-4 type rifles