XS Sights DXT2 Big Dot Yellow - S&W M&P ShieldXS DXT2 Big Dot Tritium Night Sights offer the best front sight visibility in all lighting conditions. DXT2 Big Dot sights drive focus to the front sight using a high contrast front and a V notch rear for an unobstructed view of the front sight. DXT2 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 Yellow is the best option for low light and has the