The Trijicon SRO (Specialized Reflex Optic) is specifically designed for pistol use. This optic offers wide field of view and a clean, crisp dot. This makes it easy for users to find and track the dot in target and competitive shooting applications. Improving both shooting accuracy and speed. Every SRO features a manual and automatic LED brightness modes. Additionally, a top-loading CR2032 battery provides a 3-year battery life (at setting 4 of 8). This Trijicon red dot is offered in three different dot options to better suit your needs. The choice is between a 1 MOA, 2.5 MOA or a 5 MOA. These features make the SRO a great choice in any application.