Holosun HS507C X2, BRAND NEW UNUSED, The HS507C X2 is an open reflex optical sight designed for pistol applications. The X2 Series pistol optics feature two improvements. First is the addition of Lock Mode from our 2018-2019 LE pistol optic models. Lock Mode, when activated, locks the buttons preventing inadvertent setting changes. Second, the buttons have been redesigned to compliment the Lock Mode by placing them lower and out of the way. Additional features include Holosun’s Super LED with up to 50k hours battery life, Solar Failsafe, Multi-Reticle System, and Shake Awake.