With professional shooters in mind, the Obsidian Arms guide rod is made from high quality stainless steel that has been hardened and polished for the best wear resistance and smooth cycling. Weighing in at 1.6oz the additional weight compared to the factory spring assembly will provide better muzzle control and less flip when firing. With your preferred 1911 springs you will be able to tune your P320 to the most optimal recoil for your chosen load. Obsidian Arms recommends starting with a 15lb spring. Features: High Quality Stainless Steel Compatiable with 1911 Springs 1.4oz (spring adds about 0.2oz) Limited Lifetime Manufacturer Warranty Made in the U Mfg: Obsidian Arms