XS Sights DXW Big Dot - S&W M&P SHIELDXS Sights DXW Big Dot S&W M&P SHIELD Tritium powered front sight and a white stripe rear sight allows for greater visibility in bright light and quickly changing light conditions. DXW is ideal both for target shooting and for shooters who have trouble seeing fine details or who are color blind. Since the rear sight uses white, it maintains visibility well in low light and remains a great defensive option. Snag free design for easy draw from holster