Fiber optic sight set for the Umarex NOTOS CRK PCP air rifle The Umarex NOTOS was designed to be flexible to your shooting needs. With plenty of accessory rail on the top side of the rifle, shooters can install the optic of their choice or, a set of iron sights. This matched pair of fiber optic sights sit just right for easy pick-up when the NOTOS is shouldered. The high contrast fiber optic elements pick up plenty of availale light for easy, accurate shooting in all sorts of lighting conditions. Shooters can easily install these sights in minutes.