Holosun HS407K X2 Open Reflex SightHolosun HS407K X2 Compact Open Reflex Sight for Subcompact Pistols The Holosun HS407K X2 is a compact open reflex sight purpose built for subcompact and micro compact carry pistols. The slim, low profile design fits tight slide cuts while delivering Holosun's proven reliability 50,000 hour battery life, Shake Awake technology, and a crisp 2 MOA dot for fast target acquisition. If your subcompact pistol has a K footprint slide cut, the HS407K X2 is the