Pyramid Sights Front Sight Firefly Inserts The Pyramid Sight Front Sight Firefly Insert glow sights front inserts incorporate the latest chemical and manufacturing technology to produce glow in darkness. The Firefly night sight upgrade will swap out with any of our standard nylon front sight inserts, for all of our products. The Fireflies come in two different colors (coral and yellow). Firefly insert upgrades will glow for many hours with a short exposure to a strong UV light source. Once charged, casual exposure to some ambient light will increase glow time duration. The Pyramid Sight Front Sight Firefly Insert inserts never wear out or lose their glow capabilities. One may expect decades of use with the Pyramid Firefly glow sights. Colors: Coral Yellow Thank you for your interest in our products. Check out our FAQ for answers to common questions and feel free to contact us at [email protected].