The Back Up Polymer Flip up Front Sight with standard iron sight elevationadjustment (BUPSWF) mounts onto a 1913 Picatinny rail and accepts anystandard front post blade. A standard front sight tool is required with each clickequaling the standard 1/4 MOA. Unlike other backup sights MFT has developeda shroud that shelters the front post blade from debris and impact damage whennot deployed. A slim profile allows the sight to sit under most optics.Manufactured using a specially developed Military Grade reinforced, super tough polyamide, MADE IN THE USA.BUPSWF Features and Functions:" Full Elevation adjustment, tool required" Low profile snag resistant design" Shroud protects front post blade from debris and impact damage" Accepts any standard front post blade" Can fold to the rear, the correct direction if dropped" Manufactured using a specially developed Military Grade reinforced, super tough polyamide" International shipments DO NOT require an export license, this item ships freely.