This new sight has the shape we all know and love, but it also folds and deploys using only a finger of one hand. It's extra rugged via the support angle, plus all the other features of the great conventional non folder, it also uses the standard front sight bead, and or night sight posts. Includes bayonet lug as shown. It is barrel mounted into place, via the included allen wrench. A.R.M.S.® "SILHOUETTE™" #41-B-L™ Folding Front Sight, Patent's Pending. Fits 0.750 inch diameter barrels.