Tactical backup sight is always deployed, so there's absolutely no delay, no fumbling when you need to transition from the primary optic. Troy designed this sight to be simple, rugged, and reliable-and it takes up only 1-1/8" of rail space. Precision machined from solid aluminum, with plenty of metal on the protective "ears" around the two-position aperture. All edges and corners are rounded, and there are no protruding knobs or levers to catch on brush, clothing, or other equipment. Rear of the base is undercut to provide clearance for access to the charging handle. Same-plane aperture flips easily between .190" and .070" diameter peeps, just lik Mfg: Troy Industries SPECS: 6061 T6 aluminum, hardcoat anodized, Black finish. 1.5" (3.8cm) OAL, 1.25" (3.2cm) maximum width, 1.875" (4.8cm) high from top of rail to top of sight housing. 1.8 oz. (52g) weight.