Hiviz MPSN121 Tritium Nitesight Set S&W M&P Shield 9mm/40S&W Green NITESIGHT Tritium Front & Rear Set for Smith and Wesson M&P Shield in 9mm and .40 S&W The new NITESIGHT design from HIVIZ features the latest technology in an ultra-durable, laser-sealed tactical tritium lamp to provide years of service and stand up to the roughest use. The white halo and tritium combine for ultra-fast sight acquisition in all lighting conditions and quick target acquisition in normal lighting conditions. MPSN121 sight set fits the S&W Shield in all calibers.