The UTG ACCU-SYNC Spring-loaded Flip-up Rear Sight features a tool free windage adjustment wheel, dual aiming apertures, and is precision machined from matte black anodized aircraft aluminum. Its low profile mounting base securely attaches to any Picatinny rail and uses squared recoil stops for a secure zero hold and return to zero. Our spring-loaded Posi-lock retention design locks the sight tower when it is both folded down and when it is automatically deployed, preventing the sight tower from collapsing when the sight is in use; designed to match our ACCU-SYNC Flip-up Front Sight, MNT-757.