The Yankee Hill Machine YHM-9627 is a robust, all-steel sight that perfectly aligns with the rear sight to provide you with an efficient backup iron sight. With a convenient push button, the sight folds effortlessly out of the line of vision. It also flips and locks into the deployed position with no hassle. Its installation is a breeze, thanks to the provided thumb screw. The sight is designed to accommodate all standard AR sight posts and hardware, which are included in the package.