Our new Snakeskin II mag release button has been enlarged. The unique snakeskin-machining pattern combined with the slanted profile of our button makes it extremely effective for quick mag changes. CNC machined from Stainless Steel this is a product that not only looks great & works even better. This product comes from the factory with a metric screw that will not fit a 4/40 d/t mag catch from STI. We at Shooters Connection know what a hassle it is to get apart where you have to source a screw that works so we sourced a 4/40 screw and include them in the package now at no additional cost. May require fitting.