Centra Ultima 30mm Iris 5.5-7.5 This is a premium front sight solution engineered specifically for long-range and high-power competition shooters who demand maximum precision and control. Designed for 30mm front sight housings with M30 (UN1/4"-28) threading, this advanced iris allows shooters to fine-tune their front sight picture for optimal clarity, contrast, and light management, even in rapidly changing conditions.19600004