Introducing the Strike polymer backup sights (SPBUS), a versatile and affordable sighting system designed for the AR platform, featuring built-in secondary sights for added convenience. Made from lightweight and durable SI polymer extreme material with a robust steel mounting tab and insert, these sights are built to withstand rugged conditions without issues. Installing the SPBUS is quick and easy on any picatinny rail. Both sights flip down low to stay out of the way when not in use, preventing snagging on gear. Notably, they do not feature internal springs, preventing accidental deployment. Slightly taller than standard A2 sights by 2.3mm (0.09 inches), the SPBUS is optimized for pairing both sights together rather than mixing with others. The rear sight offers dual apertures (4.70mm/0.19 inches and 1.75mm/0.07 inches) for varying eye relief needs, low-light conditions and fast target acquisition. Adjusting windage on the rear sight is easy with a knob, while front sight elevation adjustments are tool-less for quick changes. Whether used as primary sights or backups, the Strike Polymer Backup Sights (SPBUS) offer a durable, multi-functional solution at an accessible price point, ensuring reliable performance in any shooting scenario.