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

Note: Remington model 522 Viper semi-auto rimfire rifles with the following serial numbers have been observed with this part: 3024387, 3050516, 3099981, 3106813, 3112852, 3121044, 3171186, 3190437, 3203684, 3209072, 3227645, 3232240, 3232451 & 3247065.