This steel 3/8" dovetail front sight incorporates a red Fire Sight fiber optic rod, which gathers ambient light and then focuses it into a pinpoint to provide a brilliant sight picture in bright light, and a useable sight picture in low light. May require minor fitting. Blue finish. Notes:.250 narrow width is for Williams Streamlined and shorty rampsMost standard factory ramps from Winchester, Remington, Savage and others are .340 wide..531 width is for dovetailed barrels commonly found on 22 rimfire rifles and muzzleloaders