When you have nothing but a tiny pin scar to place protection for the crux on your route, it's nice to know you have the Metolius Astro Nut. Metolius made each nut out of silicon bronze for the maximum bite and strength that holds the stopper in place when you take the whipper. Its transverse taper helps you set each piece in flared garbage with ease. And Metolius color-coded and anodized each stopper's collar for easy identification, which you appreciate when you don't have the time to sort through each gear for the right piece. What climber ever has that time?