This Remington manufactured rear sight assembly includes the aperture, slide, elevation (straight slot) screw, windage screw, and (solid) base. This rear sight assembly is for the model 522 Viper semi-auto rimfire rifle and is in near excellent condition with light wear. The base mounting screws are sold separately.  (file photo)

Note: Remington model 522 Viper rimfire rifles with the following year/serial number have been observed with this part: 3193221 & 3201155