Polymer Frame Stainless Steel Slide and Barrel Equpment Rail for Tactical Lights Low Profile Three Dot Sights Matte Finish on Slide for Reduced Glare The Sigma Series is an ergonomically designed production pistol. Engineers utilizing computer analysis designed the Sigma's 18 degree grip so that the moment you raise it, your point of aim is straight, every time. Aiming a Sigma is as natural as pointing your finger! The Sigma Series is available in either 9mm or .40 S&W and both are available with a matte stainless slide and either a black frame or a NATO green frame.