The Tru Glo Tritium sights are the exact fit for the Arex Zero series pistol. These sights consist of 3 tritium vials of similar size. The Tritium Vial on the front sight has a white piece of plastic around the front tritium vial making it stick out during the day. The tritium vials on the rear sight have a black finish around which helps focus the user's eyes to the front sight. The Tritium are extremely bright compared to other tritium sights I've seen. This is a very good pistol sight for the price and would recommend it.