Complete rear sight kit replaces the standard blade on your Smith & Wesson revolver and provides a wide, V-shaped notch. Enables faster pick up of the front sight, especially with fine bead and ball front sights. Adjustable for windage. Some "J" frame models may use a smaller head diameter. The screw in this kit has a .217" diameter head. Mfg: Brownells SPECS: Kit contains sight blade, windage screw, nut, spring, and plug. Available in three blade heights: .122" fits J-frame only; .160" & .196" fit K, L, and N-frame. Blade heights measured from bottom to top of blade, not including lug.