BARSKA 6-24x50 IR AO Excavator Target Dot Riflescope 6-24x variable magnification with large 50mm objective lens in a 100% waterproof and fogproof extra rigid shockproof construction Multi-coated optics with illuminated target dot reticles Adjustable objective lens is built with a adjustable mechanism 1 inch tube construction with fast focus eyebell Bonus accessories includes set of 5/8 inch high ring, sun-shade, and flip-up covers That allows for parallax correction for specific ranges starting form 20-25 yards to infinity