The Midwest Industries Combat Fixed Rear Sight for AR15/M4/M16 Rifles and other platforms is a Mil-Spec height sight with a A2 rear sight aperture. The Combat Fixed Rear Sight is compatible with Trijicon replacement apertures (Not included). Machined from billet T6 6061 aluminum and hardcoat anodized. Adjustments are Rifle .5 MOA and Carbine .65 MOA per click. Made in the USA with a Lifetime Warranty.