The SMS2 is built in a nylon glass filled polymer and the lens has a new Si02 Quartz hard coating for extra resilience to the daily wear and tear of shooting. Its iconic design still allows shooters to co-witness with standard iron sights thanks to its incredibly low profile and unobtrusive design with rear iron sight notch.It carries on Shield's philosophy to make its users better shooters by eliminating what is not needed and providing the shooter with just one point of focus. We don't have a large sight housing blocking vision, dimmed lenses, buttons to switch or backup sights blocking the view. We make our sights to fit as close to the bore-line as possible, where a trained shooter is naturally going to present their pistol allowing for a seamless transition and a familiar but improved shooting experience. Features:Nylon glass filled polymer constructionSingle dot reticleCo-witness dot and fixed pistol sights