XS Sight Systems DXW2 Big Dot Sight Orange S&W 586/686/625/629/329 Revolvers. DXW2 Big Dot sights drive focus to the front sight using an industry leading large high-contrast front and a low profile V-notch rear. DXW2 Big Dot front sights use a patent pending glow dot that absorbs light and glows in low light levels before it is dark enough to see the tritium. Optic Orange is designed to offer a high-contrast sight picture when shooting in bright light conditions and maintain its visibility in decreasing light levels. To ensure visibility in low light when uncharged optic orange is primarily based on yellow with a hint of red. The increased surface area of the convex dot increases light absorption intensifying the charge of the glow properties of the dot. The dot-the i sight picture with a tritium dot in the front sight and a non-tritium white stripe in the rear prevents confusing the front and rear sight in high-stress situations. In most gunfights the victim and attacker are both moving and the victims focus is drawn to the threat. The wide field of view increases visibility of the front sight and of the threat downrange. Outside Diameter Big Dot 0.188"; fits in common holsters. Installation might require filing to fit sight to dovetail do not use a sight press/pusher tool. Fits S&W M&P Shield & M&P M2.0 Shield; 9mm 40S&W & 45ACP. S&W 586686625629329 Revolvers: Installation requires a drill press to drill the retaining pin hole in sight body. Might require filing to fit sight to dovetail. Specifications for XS Sight Systems DXW2 Big Dot Sight Smith & Wesson: Manufacturer: XS Sight Systems Gun Make: Smith & Wesson Color: Black Sight Style: V-Notch Fabric/Material: Steel Gun Type: Pistol Illumination Type: Tritium Features of XS Sight Systems DXW2 Big Dot Sight Smith & Wesson Steel sight with blued finish Green tritium front and non-tritium rear Green/Yellow/Orange photoluminescent ring front Snag-free design Package Contents: XS Sight Systems DXW2 Big Dot Sight Smith & Wesson XS Sight Systems SW-0035S-3N: DXW2 Big Dot Sight Orange S&W 586/686/625/629/329 Revolvers