XS makes the Tritium Rear for some pistols but not all, they said the M&P Shield rear sight was to small to put the tritium in the V without having to make both front and rear taller to accommodate the Tritium Vials . My opinion for night time use the front sight is the only one that needs the Tritium . If it is to dark to identify your target you shouldn't shoot anyway. If you can see the front sight you will put the bullet in the kill zone at self defense range of 10 yards and under.
