The HE507K-GR X2 is an open reflex optical sight designed for subcompact pistol applications. The HE507K-GR X2 improves on the previous version by adding Lock Mode, which was first introduced in their 2018 LEM pistol optic models. Lock Mode, when activated, locks the buttons preventing inadvertent setting changes. Additional features include Holosun’s Green Super LED with up to 50k hour battery life, Multi-Reticle System, and Shake Awake. The durable housing is made from 7075 Aluminum, uses Holosun’s K footprint, and houses the 1632 battery in a side-mounted tray for easy replacement when needed.