Utilizing 17-4 Stainless Steel heat treated to over H900 condition, the Sonus is engineered to be ultralight at only 9.8oz without sacrificing durability. The precision engineered 17-4 design allows for thinner walls which not only optimize low weight but also increases internal volume while maintaining a smaller outer envelope. The Sonus is designed for 9mm handguns and threads directly to a threaded barrel using the standard 1/2x28 TPI thread pattern. This model has a burnt bronze finish. *Sound reduction ratings are approximate based on measurements by the manufacturer and may vary depending on firearm setup and environmental factors.*