HE407K Green dot pistol optic - HolosunHolosun is the industry leader in bringing feature rich, high quality products at a price that wont leave you stranded for ammo money. The HE407K GR X2 is an open reflex optical sight designed for subcompact pistol applications. The HE407K GR X2 improves on previous the version by adding Lock Mode which was first introduced in our 2018 LEM pistol optic models. Lock Mode, when activated, locks the buttons preventing inadvertent setting changes.