The Costa Ludus sights were designed with direction from Chris Costa, based on his extensive background with the United States Coast Guard and as a firearms instructor. These sights have several unique features that set them apart from other Night Fision sights. Most notably, there are serrations on the front and rear sights to reduce glare. There are also serrations on the front edge of the rear sight to maximize one-handed manipulation. Costa Ludus sights include a proprietary Night Fision Perfect Dot in the front sight and a horizontal tritium bar in the rear sight. The tritium bar gives the shooter a clear distinction between the front and rear sights in low light conditions. The rear sight is also cut to maximize the target picture for fast acquisition. Our patented, injection molded sleeve design not only holds our tritium vials securely in place, it creates a brighter and more durable ring, we call The Perfect Dot, that provides maximum visibility both day and night. CNC Machined out of high quality steel. Black Nitride coating used to improve wear and corrosion resistance. Gunsmith Recommended for installation. These sights offer an extreme low profile co-witness. They are recommended for use with a Holosun c-series or Trijicon RMR Type 2 mini-red dot optic. It is highly recommended you compare the blade height with your optic housing height to ensure where they fall in your window. Built in the USA with Swiss Tritium. Front Sight Width: 0.140". Front Sight Height: 0.299". Rear Sight Height: 0.330".